1962 First U.S. Air Force plane crashes in South Vietnam.

The first U.S. Air Force plane is lost in South Vietnam. The C-123 aircraft crashed while spraying defoliant on a Viet Cong ambush site.

The aircraft was part of Operation Ranch Hand, a technological area-denial technique designed to expose the roads and trails used by the Viet Cong. U.S. personnel dumped an estimated 19 million gallons of defoliating herbicides over 10-20 percent of Vietnam and parts of Laos from 1962 to 1971. Agent Orange--so named from the color of its metal containers--was the most frequently used.

The operation succeeded in killing vegetation but not in stopping the Viet Cong. The use of these agents was controversial, both during and after the war, because of questions about long-term ecological impacts and the effect on humans who handled or were sprayed by the chemicals. Beginning in the late 1970s, Vietnam veterans began to cite the herbicides, especially Agent Orange, as the cause of health problems ranging from skin rashes to cancer and birth defects in their children. Similar problems, including an abnormally high incidence of miscarriages and congenital malformations, have been reported among the Vietnamese people who lived in the areas where the defoliate agents were used.

1970 Antiwar protestors sue Dow Chemical

Antiwar protestors take legal action in an attempt to prove that the Dow Chemical Company is still making napalm. Dow had claimed that it had stopped making napalm. Members of the antiwar movement filed suit against the Dow Chemical Company in a Washington, D.C., court. The plaintiffs were trying to force the company to disclose all government contracts to prove that the company was still making napalm.

1955 Diem institutes limited agrarian reforms

After months of prodding by U.S. advisors, South Vietnamese President Ngo Dinh Diem introduces the first in a series of agrarian reform measures. This first measure was a decree governing levels of rent for farmland.

U.S. officials had strongly urged that Diem institute such reforms to win the support of the common people, but later critics maintained his land reform program began too late, progressed too slowly, and never went far enough. What the South Vietnamese farmers wanted was a redistribution of land from the absentee landlords to those that actually worked the fields, but Diem's program to return the land to the tiller was implemented halfheartedly and did little to meet the rising appetite for land among South Vietnam's rural population. Provisions for payment by peasants granted land created unnecessary hardships. Although 1 million tenants received some relief, more than 1 million received no land at all, and the lack of impartial enforcement agencies crippled many potential benefits. Instead of redistributing land to the poor, Diem's land reform program ended up taking back what the peasants had been given by the Viet Minh and returning it to the landlords, forcing peasants to pay for the land they considered theirs on impossible terms. In 1960, 75 percent of the land was owned by 15 percent of the people. The communists capitalized on unresolved peasant unrest throughout Diem's regime. Discontent towards Diem reached its height when dissident South Vietnamese officers murdered him during a coup in November 1963.

1970 Senate Foreign Relations Committee opens hearings

The Senate Foreign Relations Committee opens hearings on the conduct of the war by the Nixon administration. Senator Charles Goodell (R-New York) said that Vietnamization (President Richard Nixon's program to transfer war responsibility to the South Vietnamese) had been a "great public relations success." Taking exception with Senator Goodell's assessment, Senators Harold Hughes (D-Iowa), Thomas Eagleton (D-Missouri), and Alan Cranston (D-California) testified in support of a Senate resolution calling for the termination of the American commitment to South Vietnam unless the Saigon government took steps to broaden its cabinet, stop press censorship, and release political prisoners.

1962 First U.S. helicopter is shot down in Vietnam.

The first U.S. helicopter is shot down in Vietnam. It was one of 15 helicopters ferrying South Vietnamese Army troops into battle near the village of Hong My in the Mekong Delta.

The first U.S. helicopter unit had arrived in South Vietnam aboard the ferry carrier USNS Core on December 11, 1961. This contingent included 33 Vertol H-21C Shawnee helicopters and 400 air and ground crewmen to operate and maintain them. Their assignment was to airlift South Vietnamese Army troops into combat.

1965 Rumors fly about U.S.-Soviet pressure on allies in Vietnam

McGeorge Bundy, American Special Assistant for National Security, arrives in Saigon for talks with U.S. Ambassador General Maxwell Taylor. Two days later Soviet Premier Aleksei Kosygin arrived in Hanoi. There was worldwide speculation that their visits were linked--that the United States and the Soviet Union had agreed to pressure their "clients" into negotiations--but this was denied by all the principals. Bundy, in fact, was there to confer with Ambassador Taylor on the best way to deal with the political situation. And although Kosygin publicly proclaimed continued Soviet support for North Vietnam and the communist war, a Soviet participant in the talks later described the North Vietnamese as "a bunch of stubborn bastards."

1972 Last Thai contingent departs South Vietnam

A force of 824 soldiers, the last of Thailand's 12,000 troops serving in South Vietnam, departs. The Thai contingent, which had first arrived in country in the fall of 1967, had been part of the Free World Military Forces, an effort by President Lyndon B. Johnson to enlist allies for the United States and South Vietnam. By securing support from other nations, Johnson hoped to build an international consensus behind his policies in Vietnam. The effort was also known as the "many flags" program. In all, 44 countries responded to Johnson plea for military aid to South Vietnam, but only Australia, New Zealand, Korea, and Thailand provided combat troops. In the end, the program never achieved the widespread international support that Johnson sought.

1960 South Vietnam requests more support

The South Vietnamese government requests that Washington double U.S. Military Assistance and Advisory Group (MAAG-Vietnam) strength from 342 to 685. The advisory group was formed on November 1, 1955 to provide military assistance to South Vietnam. It had replaced U.S. Military Assistance Advisory Group Indochina (MAAG-Indochina), which had been providing military assistance to "the forces of France and the Associated States in Indochina" (Cambodia, Laos and Vietnam) in accordance with President Harry S. Truman's order of June 27, 1950.

MAAG-Vietnam had U.S. Army, Navy, Air Force, and Marine Corps elements that provided advice and assistance to the South Vietnamese Ministry of Defense, Joint General Staff and corps and division commanders, as well as to training centers and province and district headquarters.

In May 1964, MAAG-Vietnam was disbanded and its personnel and responsibilities absorbed by the U.S. Military Assistance Command Vietnam (MACV), which had been established in Saigon two years earlier.

1975 North Vietnamese begin preparations for offensive

North Vietnamese Gen. Van Tien Dung departs for South Vietnam to take command of communist forces in preparation for a new offensive. In December 1974, the North Vietnamese 7th Division and the newly formed 3rd Division attacked Phuoc Long Province, north of Saigon. This attack represented an escalation in the "cease-fire war" that started shortly after the Paris Peace Accords were signed in 1973.

The North Vietnamese wanted to see how Saigon and Washington would react to a major attack so close to Saigon. President Richard Nixon and his successor, Gerald Ford, had promised to come to the aid of South Vietnam if the North Vietnamese launched a major new offensive. With Nixon's Watergate resignation and Ford facing an increasingly hostile Congress, Hanoi was essentially conducting a "test" attack to see if the United States would honor its commitment to Saigon. The attack was much more successful than the North Vietnamese anticipated: the South Vietnamese soldiers fought poorly and the United States did nothing.

Emboldened by their success, the North Vietnamese decided to launch a major offensive against the South Vietnamese. "Campaign 275" began on March 1, 1975. The North Vietnamese forces quickly overran the South Vietnamese and the United States failed to provide the promised support. Saigon fell on April 30 and the South Vietnamese government officially surrendered.

1966 Johnson meets with South Vietnamese Premier

Accompanied by his leading political and military advisers, U.S. President Lyndon B. Johnson meets with South Vietnamese Premier Nguyen Cao Ky in Honolulu.

The talks concluded with issuance of a joint declaration in which the United States promised to help South Vietnam "prevent aggression," develop its economy, and establish "the principles of self-determination of peoples and government by the consent of the governed." Johnson declared: "We are determined to win not only military victory but victory over hunger, disease, and despair." He announced renewed emphasis on "The Other War"--the effort to provide the South Vietnamese rural population with local security, and economic and social programs to win over their active support. In his final statement on the discussions, Johnson warned the South Vietnamese that he would be monitoring their efforts to build democracy, improve education and health care, resettle refugees, and reconstruct South Vietnam's economy.

1973 ICCS take up positions

Supervisors from the International Commission of Control and Supervision (ICCS), delegated to oversee the cease-fire, start to take up their positions.

The cease-fire had gone into effect as a provision of the Paris Peace Accords. The ICCS included representatives from Canada, Poland, Hungary, and Indonesia, and was supposed to supervise the cease-fire. However, the ICCS had no enforcement powers and had extreme difficulty in settling the many quarrels that quickly arose. In the end, the ICCS proved incapable of enforcing the provisions of the Accords and was largely ineffectual. Consequently, renewed fighting between the South and North Vietnamese broke out after only a brief lull and continued for the next two years, until the North Vietnamese successfully launched their final offensive in 1975 and South Vietnam surrendered.

1965 U.S. jets conduct retaliatory raids

As part of Operation Flaming Dart, 49 U.S. Navy jets from the 7th Fleet carriers Coral Sea and Hancock drop bombs and rockets on the barracks and staging areas at Dong Hoi, a guerrilla training camp in North Vietnam. Escorted by U.S. jets, a follow-up raid by South Vietnamese planes bombed a North Vietnamese military communications center.

These strikes were in retaliation for communist attacks on the U.S. installation at Camp Holloway and the adjacent Pleiku airfield in the Central Highlands, which killed eight U.S. servicemen, wounded 109, and destroyed or damaged 20 aircraft.

Even before the attack, presidential advisors John T. McNaughton and McGeorge Bundy had favored bombing North Vietnam. After the attack in the Central Highlands, they strongly urged President Johnson to order the retaliatory raids. Johnson agreed and gave the order to commence Operation Flaming Dart, hoping that a quick and effective retaliation would persuade the North Vietnamese to cease their attacks in South Vietnam.

Bundy, who had just returned from Vietnam, defended the air raids as "right and necessary." Senate Majority Leader Mansfield (D-Montana) and GOP leader Everett Dirksen (Illinois) supported the president's decision, but Senators Wayne Morse (D-Oregon) and Ernest Gruening (D-Alaska) attacked the action as a dangerous escalation of the war.

The retaliatory raids did not have the desired effect. On February 10, the Viet Cong struck again, this time at an American installation in Qui Nhon, killing 23 Americans. Johnson quickly ordered another retaliatory strike, Flaming Dart II.

1971 Operation Dewey Canyon II ends

Operation Dewey Canyon II ends, but U.S. units continue to provide support for South Vietnamese army operations in Laos. Operation Dewey Canyon II began on January 30 as the initial phase of Lam Son 719, the South Vietnamese invasion of Laos that was to commence on February 8. The purpose of the South Vietnamese operation was to interdict the Ho Chi Minh Trail, advance to Tchepone in Laos, and destroy the North Vietnamese supply dumps in the area.

In Dewey Canyon II, the vanguard of the U.S. 1st Brigade, 5th Infantry Division, an armored cavalry/engineer task force, cleared the road from Vandegrift Combat Base (southwest of Cam Lo in the region south of the DMZ) along highway Route 9 toward Khe Sanh. The area was cleared so that 20,000 South Vietnamese troops could reoccupy 1,000 square miles of territory in northwest South Vietnam and mass at the Laotian border in preparation for the invasion of Laos. In accordance with a U.S. congressional ban, U.S. ground forces were not to enter Laos. Instead, the only direct U.S. support permitted was long-range cross-border artillery fire, fixed-wind air strikes, and 2,600 helicopters to airlift Saigon troops and supplies.

1962 MACV established

The Military Assistance Command Vietnam (MACV), headed by Gen. Paul D. Harkins, former U.S. Army Deputy Commander-in-Chief in the Pacific, is installed in Saigon as the United States reorganizes its military command in South Vietnam.

Before MACV, the senior U.S. military command in South Vietnam was the U.S. Military Assistance and Advisory Group (MAAG-Vietnam), which was formed on November 1, 1955 to provide military assistance to South Vietnam. MAAG-Vietnam had U.S. Army, Navy, Air Force, and Marine Corps elements that provided advice and assistance to the South Vietnamese Ministry of Defense, Joint General Staff and corps and division commanders, as well as to training centers and province and district headquarters.

MAAG-Vietnam was disbanded in 1964 and its personnel and responsibilities absorbed by MACV. The establishment of MACV, which greatly enlarged and reorganized the advisory effort, represented a substantial increase in the U.S. commitment to the war in Vietnam, and American assistance to the South Vietnamese doubled between 1961 and 1962. Thereafter, the conduct of the war was directed by MACV and a major build-up of American advisers, support personnel, and eventually an escalation that included the commitment of U.S. combat troops began.

1971 Operation Lam Son 719 begins

South Vietnamese army forces invade southern Laos. Dubbed Operation Lam Son 719, the mission goal was to disrupt the communist supply and infiltration network along Route 9 in Laos, adjacent to the two northern provinces of South Vietnam.

The operation was supported by U.S. airpower (aviation and airlift) and artillery (firing across the border from firebases inside South Vietnam). Observers described the drive on North Vietnam's supply routes and depots as some of the bloodiest fighting of the war. Enemy resistance was initially light, as a 12,000-man spearhead of the South Vietnamese army thrust its way across the border into the communists' deepest jungle stronghold--the town of Tchepone, a major enemy supply center on Route 9, was their major objective. However, resistance stiffened in the second week when the North Vietnamese rushed reinforcements to the area. During the last week of February, the big push bogged down about 16 miles from the border, after bloody fighting in which the communist troops overran two South Vietnamese army battalions.

Also on this day: In Cambodia, Premier Lon Nol suffers a paralyzing stroke and turns his duties over to Deputy Premier Sirik Matak. Debilitated by the stroke, Lon Nol resigned on April 20. A week later, he withdrew his resignation, staying on in a figurehead role as Sirik Matak continued to run the government pending his recovery.

1965 U.S. sends first combat troops to South Vietnam

A U.S. Marine Corps Hawk air defense missile battalion is deployed to Da Nang. President Johnson had ordered this deployment to provide protection for the key U.S. airbase there.

This was the first commitment of American combat troops in South Vietnam and there was considerable reaction around the world to the new stage of U.S. involvement in the war. Predictably, both communist China and the Soviet Union threatened to intervene if the United States continued to apply its military might on behalf of the South Vietnamese. In Moscow, some 2,000 demonstrators, led by Vietnamese and Chinese students and clearly supported by the authorities, attacked the U.S. Embassy. Britain and Australia supported the U.S. action, but France called for negotiations.

1972 USS Constellation arrives off coast of Vietnam.

The aircraft carrier USS Constellation joins aircraft carriers Coral Sea and Hancock off the coast of Vietnam. From 1964 to 1975, there were usually three U.S. carriers stationed in the water near Vietnam at any given time. Carrier aircraft participated in the bombing of North Vietnam and also provided close air support for U.S. and South Vietnamese forces in South Vietnam. In 1972, the number of U.S. carriers off Vietnam increased to seven as part of the U.S. reaction to the North Vietnamese Eastertide Offensive that was launched on March 30--carrier aircraft played a major role in the air operations that helped the South Vietnamese defeat the communist invasion.

1965 Viet Cong blow up U.S. barracks

Viet Cong guerrillas blow up the U.S. barracks at Qui Nhon, 75 miles east of Pleiku on the central coast, with a 100-pound explosive charge under the building. A total of 23 U.S. personnel were killed, as well as two Viet Cong. In response to the attack, President Lyndon B. Johnson ordered a retaliatory air strike operation on North Vietnam called Flaming Dart II.

This was the second in a series of retaliations launched because of communist attacks on U.S. installations in South Vietnam. Just 48 hours before, the Viet Cong struck Camp Holloway and the adjacent Pleiku airfield in the Central Highlands. This attack killed eight U.S. servicemen, wounded 109, and destroyed or damaged 20 aircraft.

With his advisors advocating a strong response, President Johnson gave the order to launch Operation Flaming Dart, retaliatory air raids on a barracks and staging areas at Dong Hoi, a guerrilla training camp 40 miles north of the 17th parallel in North Vietnam.

Johnson hoped that quick and effective retaliation would persuade the North Vietnamese to cease their attacks in South Vietnam.

Unfortunately, Operation Flaming Dart did not have the desired effect. The attack on Qui Nhon was only the latest in a series of communist attacks on U.S. installations, and Flaming Dart II had very little effect.

1971 Journalists killed in helicopter crash

Four journalists, including photographer Larry Burrows of Life magazine, Kent Potter of United Press International, Nenri Huett of the Associated Press, and Keisaburo Shimamoto of Newsweek, die in a South Vietnamese helicopter operating in Laos. The journalists had been covering Operation Lam Son 719, a limited attack into Laos by South Vietnamese forces, when their helicopter crashed.

Vietnam was one of the most reported conflicts in the history of warfare. In 1964, when the massive American buildup began, there were roughly 40 U.S. and foreign journalists in Saigon. By August 1966, there were over 400 news media representatives in South Vietnam from 22 nations. The Vietnam War correspondents in the field shared the same dangers that confronted the front-line troops, risking their lives to witness and report the realities of the battlefield. Sixteen Americans lost their lives while covering the war. American journalists are among the 42 U.S. civilians still missing in action and unaccounted for in Southeast Asia, including NBC News correspondent Welles Hangen and Time photographer Sean Flynn, both of whom disappeared while covering the war in Cambodia.

1972 Cambodians launch attack to retake Angkor Wat

About 6,000 Cambodian troops launch a major operation to wrestle the religious center of Angkor Wat from 4,000 North Vietnamese troops entrenched around the famous Buddhist temple complex, which had been seized in June 1970. Fighting continued throughout the month. Even with the addition of 4,000 more troops, the Cambodians were unsuccessful, and eventually abandoned their efforts to expel the North Vietnamese.

1973 Release of U.S. POWs begins

The release of U.S. POWs begins in Hanoi as part of the Paris peace settlement. The return of U.S. POWs began when North Vietnam released 142 of 591 U.S. prisoners at Hanoi's Gia Lam Airport. Part of what was called Operation Homecoming, the first 20 POWs arrived to a hero's welcome at Travis Air Force Base in California on February 14. Operation Homecoming was completed on March 29, 1973, when the last of 591 U.S. prisoners were released and returned to the United States.

1965 Johnson approves Operation Rolling Thunder

President Lyndon B. Johnson decides to undertake the sustained bombing of North Vietnam that he and his advisers have been contemplating for a year.

Earlier in the month, the president had ordered Operation Flaming Dart in response to communist attacks on U.S. installations in South Vietnam. These retaliatory raids did not have the desired effect of causing the North Vietnamese to cease support of Viet Cong forces in South Vietnam, and out of frustration, Johnson turned to a more extensive use of airpower.

Called Operation Rolling Thunder, the bombing campaign was designed to interdict North Vietnamese transportation routes in the southern part of North Vietnam and slow infiltration of personnel and supplies into South Vietnam. The first Rolling Thunder mission took place on March 2, 1965, when 100 U.S. Air Force and Republic of Vietnam Air Force (VNAF) planes struck the Xom Bang ammunition dump 100 miles southeast of Hanoi.

In July 1966, Rolling Thunder was expanded to include North Vietnamese ammunition dumps and oil storage facilities, and in the spring of 1967, it was further expanded to include power plants, factories, and airfields in the Hanoi-Haiphong area.

Operation Rolling Thunder was closely controlled by the White House and at times targets were personally selected by President Johnson. From 1965 to 1968, about 643,000 tons of bombs were dropped on North Vietnam. A total of nearly 900 U.S. aircraft were lost during Operation Rolling Thunder. The operation continued, with occasional suspensions, until President Johnson, under increasing domestic political pressure, halted it on October 31, 1968.

1968 Additional troops ordered to South Vietnam

As an emergency measure in response to the 1968 communist Tet Offensive, Secretary of Defense Robert McNamara approves the deployment of 10,500 troops to cope with threats of a second offensive. The Joint Chiefs of Staff, who had argued against dispatching any reinforcements at the time because it would seriously deplete the strategic reserve, immediately sent McNamara a memorandum asking that 46,300 reservists and former servicemen be activated. Not wanting to test public opinion on what would no doubt be a controversial move, Johnson consigned the issue of the reservists to "study." Ultimately, he decided against a large-scale activation of the reserve forces.

1962 Kennedy authorizes U.S. advisors to fire in self-defense

President John F. Kennedy authorizes U.S. military advisors in Vietnam to return fire if fired upon. At a news conference, he said, "The training missions we have [in South Vietnam] have been instructed that if they are fired upon, they are of course to fire back, but we have not sent combat troops in [the] generally understood sense of the word." In effect, Kennedy was acknowledging that U.S. forces were involved in the fighting, but he wished to downplay any appearance of increased American involvement in the war. The next day former Vice President Nixon expressed hopes that President Kennedy would "step up the build-up and under no circumstances curtail it because of possible criticism."

1970 Gallup Poll released

Despite an increasingly active antiwar movement, a Gallup Poll shows that a majority of those polled (55 percent) oppose an immediate withdrawal of U.S. troops from Vietnam. Those that favored American withdrawal had risen from 21 percent, in a November poll, to 35 percent. President Nixon had taken office in January 1969 promising to bring the war to an end, but a year later the fighting continued and support for the president's handling of the war had begun to slip significantly.

1970 Chicago Eight defense attorneys sentenced

As the jury continues to deliberate in the trial of the Chicago Eight, defense attorneys William Kunstler and Leonard Weinglass and three of the defendants are sentenced to prison for contempt of court.

The trial for eight antiwar activists charged with the responsibility for the violent demonstrations at the August 1968 Democratic National Convention took place in Chicago. The defendants included David Dellinger of the National Mobilization Committee (NMC); Rennie Davis and Thomas Hayden of the Students for a Democratic Society (SDS); Abbie Hoffman and Jerry Rubin, founders of the Youth International Party ("Yippies"); Bobby Seale of the Black Panthers; and two lesser known activists, Lee Weiner and John Froines.

They were charged with conspiracy to cross state lines with intent to incite a riot. Attorneys William Kunstler and Leonard Weinglass represented all but Seale. The trial, presided over by Judge Julius Hoffman, turned into a circus as the defendants and their attorneys used the court as a platform to attack Nixon, the war, racism, and oppression. Their tactics were so disruptive that at one point, Judge Hoffman ordered Seale gagged and strapped to his chair--Seale's disruptive behavior eventually caused the judge to try him separately.

By the time the trial ended in February 1970, Judge Hoffman had found all the defendants and their attorneys guilty of 175 counts of contempt of court and sentenced them to terms between two to four years. Although declaring the defendants not guilty of conspiracy, the jury found all but Froines and Weiner guilty of intent to riot. The others were each sentenced to five years and fined $5,000. None served time because a 1972 Court of Appeals decision overturned the criminal convictions; eventually, most of the contempt charges were also dropped.

1966 DeGaulle offers to help end Vietnam War

In response to a letter from Ho Chi Minh asking that French President Charles De Gaulle use his influence to "prevent perfidious new maneuvers" by the United States in Southeast Asia, De Gaulle states that France is willing to do all that it could to end the war. As outlined by De Gaulle, the French believed that the Geneva agreements should be enforced, that Vietnam's independence should be "guaranteed by the nonintervention of any outside powers," and that the Vietnamese government should pursue a "policy of strict neutrality." President Lyndon Johnson saw De Gaulle's proposal as part of a continuing effort by the French leader to challenge U.S. leadership in Southeast Asia as well as in Europe. Seeing the American commitment in Vietnam as part of a larger global issue of American credibility, Johnson believed that the United States could not afford to abandon its South Vietnamese ally and rejected De Gaulle's proposal without consideration.

1966 Taylor testifies on Operation Rolling Thunder

In testimony before the Senate Foreign Relations Committee, Gen. Maxwell Taylor states that a major U.S. objective in Vietnam is to demonstrate that "wars of liberation" are "costly, dangerous and doomed to failure." Discussing the American air campaign against North Vietnam, Taylor declared that its primary purpose was "to change the will of the enemy leadership."

The decision to launch a bombing campaign against North Vietnam was controversial. President Lyndon B. Johnson deliberated for a year before deciding to undertake the sustained bombing of North Vietnam. Earlier in the month, he had ordered Operation Flaming Dart in response to communist attacks on U.S. installations in South Vietnam. It was hoped that these retaliatory raids would cause the North Vietnamese to cease support of Viet Cong forces in South Vietnam, but they did not have the desired effect. Out of frustration, Johnson initiated Operation Rolling Thunder.

The new bombing campaign was designed to interdict North Vietnamese transportation routes in the southern part of North Vietnam and thereby slow infiltration of personnel and supplies into South Vietnam. The first Rolling Thunder mission took place on March 2, 1965, when 100 U.S. Air Force and Republic of Vietnam Air Force (VNAF) planes struck the Xom Bang ammunition dump 100 miles southeast of Hanoi. Rolling Thunder continued, with occasional suspensions, until President Johnson, under intense domestic political pressure, halted it on October 31, 1968.

Operation Rolling Thunder was closely controlled by the White House and at times targets were personally selected by President Johnson. From 1965 to 1968, an estimated 643,000 tons of bombs were dropped on North Vietnam. A total of nearly 900 U.S. aircraft would be lost during Operation Rolling Thunder.

1968 U.S. casualty rate reaches record high

American officials in Saigon report an all-time high weekly rate of U.S. casualties--543 killed in action and 2,547 wounded in the previous seven days. These losses were a result of the heavy fighting during the communist Tet Offensive.

1965 South Vietnamese coup unsuccessful

Dissident officers move several battalions of troops into Saigon on this day with the intention of ousting Gen. Nguyen Khanh from leadership.

General Khanh escaped to Dalat with the aid of Air Vice Marshal Nguyen Cao Ky, commander of the South Vietnamese Air Force, who then threatened to bomb Saigon and the Tan Son Nhut Airport unless the rebel troops were withdrawn. Ky was dissuaded from this by Gen. William Westmoreland, Commander of U.S. Military Assistance Command Vietnam, who told Ky that more political instability might have a negative impact on continued U.S. aid. Khanh was able to get troops to take over from the insurgents without any resistance on February 20.

Meanwhile, Ky met with the dissident officers and agreed to their demand for the dismissal of Khanh. On February 21, the Armed Forces Council dismissed Khanh as chairman and as commander of the armed forces. General Lam Van Phat replaced him. The next day, Khanh announced that he had accepted the council's decision, after which he was appointed a "roving ambassador," assigned first to go to the United Nations and present evidence that the war in South Vietnam was being directed from Hanoi by the North Vietnamese.

1970 Chicago Seven sentenced

The Chicago Seven (formerly the Chicago Eight--one defendant, Bobby Seale, was being tried separately) are acquitted of riot conspiracy charges, but found guilty of inciting riot.

The eight antiwar activists were charged with the responsibility for the violent demonstrations at the August 1968 Democratic National Convention in Chicago. The defendants included David Dellinger of the National Mobilization Committee (NMC); Rennie Davis and Thomas Hayden of the Students for a Democratic Society (SDS); Abbie Hoffman and Jerry Rubin, founders of the Youth International Party ("Yippies"); Bobby Seale of the Black Panthers; and two lesser known activists, Lee Weiner and John Froines.

The defendants were charged with conspiracy to cross state lines with intent to incite a riot. Attorneys William Kunstler and Leonard Weinglass represented all but Seale. The trial, presided over by Judge Julius Hoffman, turned into a circus as the defendants and their attorneys used the court as a platform to attack Nixon, the Vietnam War, racism, and oppression. Their tactics were so disruptive that at one point, Judge Hoffman ordered Seale gagged and strapped to his chair-Seale's behavior eventually caused the judge to try him separately.

By the time the trial ended in February 1970, Hoffman had found the defendants and their attorneys guilty of 175 counts of contempt of court and sentenced them to terms between two to four years. Although declaring the defendants not guilty of conspiracy, the jury found all but Froines and Weiner guilty of intent to riot. The others were each sentenced to five years and fined $5,000. However, none served time because in 1972, a Court of Appeal overturned the criminal convictions and eventually most of the contempt charges were also dropped.

1970 Kissinger begins secret negotiations with North Vietnamese

National Security Advisor Henry Kissinger begins secret peace talks with North Vietnamese representative Le Duc Tho, the fifth-ranking member of the Hanoi Politburo, at a villa outside Paris.

Le Duc Tho stated that the North Vietnamese position continued to require an unconditional U.S. withdrawal on a fixed date and the abandonment of the Thieu government as a precondition for further progress, which stalled the negotiations. The North Vietnamese rejected Kissinger's proposals for a mutual withdrawal of military forces, the neutralization of Cambodia, and a mixed electoral commission to supervise elections in South Vietnam. The other two meetings, in which there was a similar lack of progress, were held on March 16 and April 4.

1967 Bernard Fall killed by mine in South Vietnam

Writer and historian Bernard B. Fall is killed by a Viet Cong mine while accompanying a U.S. Marine patrol along the seacoast about 14 miles northwest of Hue, on a road known as the "Street Without Joy" (which Fall had used for the title of one of his books about the war). A professor of international relations at Howard University in Washington, D.C., Fall was a French citizen and noted expert on the war in Vietnam. He was killed while gathering material for his eighth book. A U.S. Marine photographer was also killed.

1972 Nixon visits China

President Richard Nixon visits the People's Republic of China. After arriving in Beijing, the president announced that his breakthrough visit to China is "The week that changed the world." In meeting with Nixon, Prime Minister Zhou Enlai urged early peace in Vietnam, but did not endorse North Vietnam's political demands. North Vietnamese officials and peace negotiators took a dim view of Nixon's trip, fearing that China and the United States would make a deal behind their backs. Nixon's promise to reduce the U.S. military presence on Taiwan seemed to confirm North Vietnam's fears of a Chinese-American sellout-trading U.S. military reduction in Taiwan for peace in Vietnam. Despite Hanoi's fears, China continued to supply North Vietnam levels of aid that had increased significantly in late 1971. This aid permitted the North Vietnamese to launch a major new offensive in March 1972.

1965 Westmoreland asks for Marines

General William Westmoreland, commander of Military Assistance Command Vietnam, cables Washington, D.C., to request that two battalions of U.S. Marines be sent to protect the U.S. airbase at Da Nang.

Ambassador Maxwell Taylor, aware of Westmoreland's plan, disagreed and cabled President Lyndon B. Johnson from Saigon to warn that such a step would encourage South Vietnam to "shuck off greater responsibilities." The Joint Chiefs of Staff, however, supported Westmoreland's request and on February 26, White House officials cabled Taylor and Westmoreland that the troops would be sent, and that Taylor should "Secure GVN [Government of South Vietnam] approval." General Westmoreland later insisted that he did not regard his request as "the first step in a growing American commitment," but by 1969 there were over 540,000 American troops in South Vietnam.

1967 Operation Junction City begins

Operation Junction City is launched to ease pressure on Saigon. It was an effort to smash the Viet Cong's stronghold in Tay Ninh Province and surrounding areas along the Cambodian border northwest of Saigon.

The purpose of the operation was to drive the Viet Cong away from populated areas and into the open, where superior American firepower could be more effectively used. In the largest operation of the war to date, four South Vietnamese and 22 U.S. battalions were involved--more than 25,000 troops. The first day's operation was supported by 575 aircraft sorties, a record number for a single day in South Vietnam. The operation was marked by one of the largest airmobile assaults in history when 240 troop-carrying helicopters descended on the battlefield. There were 2,728 enemy casualties by the end of the operation on March 17.

1971 South Vietnamese advance stalls

In Operation Lam Son 719, the South Vietnamese advance into Laos grinds to a halt.

The operation began on February 8. It included a limited incursion by South Vietnamese forces into Laos to disrupt the communist supply and infiltration network in Laos along Route 9 adjacent to the two northern provinces of South Vietnam. The operation was supported by U.S. airpower (aviation and airlift) and artillery (firing across the border from firebases inside South Vietnam).

Observers described the drive on Hanoi's supply routes and depots as some of the "bloodiest fighting" of the war. Enemy resistance was initially light as a 12,000-man spearhead of the South Vietnamese army thrust its way across the border into the communists' deepest jungle stronghold, with the town of Tchepone, a major enemy supply center on Route 9 in Laos, as the major objective. However, resistance stiffened in the second week as the North Vietnamese rushed reinforcements to the area. On this day, the big push bogged down around 16 miles from the border, after bloody fighting in which the communist troops overran two South Vietnamese battalions.

1966 Desertion up in South Vietnamese army

According to the U.S. military headquarters in Saigon, 90,000 South Vietnamese deserted in 1965. This number was almost 14 percent of total South Vietnamese army strength and was twice the number of those that deserted in 1964. By contrast, the best estimates showed that fewer than 20,000 Viet Cong defected during the previous year.

1968 Hue recaptured

The Imperial Palace in Hue is recaptured by South Vietnamese troops. Although the Battle of Hue was not officially declared over for another week, it was the last major engagement of the Tet Offensive.

At dawn on the first day of the Tet holiday truce, Viet Cong forces, supported by large numbers of North Vietnamese troops, launched the largest and best-coordinated offensive of the war, driving into the center of South Vietnam's seven largest cities and attacking 30 provincial capitals ranging from the Delta to the DMZ. Among the cities taken during the first four days of the offensive were Hue, Dalat, Kontum, and Quang Tri; in the north, all five provincial capitals were overrun. At the same time, enemy forces shelled numerous allied airfields and bases.

Nearly 1,000 Viet Cong were believed to have infiltrated Saigon, and it required a week of intense fighting by an estimated 11,000 U.S. and South Vietnamese troops to dislodge them. By February 10, the offensive was largely crushed, but with heavy casualties on both sides. The former Imperial capital of Hue took almost a month of savage house-to-house combat to regain. The city had come under attack by two North Vietnamese regiments on January 31 and eventually elements of three North Vietnamese divisions were involved in the fight. The main battle centered on the Citadel, a two-square mile fortress with walls 30 feet high and 20 feet thick built in 1802. It took eight battalions of U.S. Marines and troopers from the 1st Cavalry Division plus eleven South Vietnamese battalions to evict the communists from the city. It was a costly battle. The U.S. Army suffered 74 dead and 507 wounded; the U.S. Marines lost 142 dead and 857 wounded. South Vietnamese losses totaled 384 dead and 1,830 wounded. North Vietnamese casualties included 5,000 dead and countless more wounded.

1969 Airman wins Medal of Honor for action on this day

After a North Vietnamese mortar shells rocks their Douglas AC-47 gunship, Airman First Class John L. Levitow throws himself on an activated, smoking magnesium flare, drags himself and the flare to the open cargo door, and tosses it out of the aircraft just before it ignites. For saving his fellow crewmembers and the gunship, Airman Levitow was later awarded the Medal of Honor. He was the only enlisted airmen to win the Medal of Honor in Vietnam and was one of only four enlisted airmen ever to win the medal.

1971 Congress moves to block widening of the war

In both houses of Congress, legislation is initiated to forbid U.S. military support of any South Vietnamese invasion of North Vietnam without congressional approval. This legislation was a result of the controversy that arose after the invasion of Laos by South Vietnamese forces in Operation Lam Son 719. On February 8, South Vietnamese forces had launched a major cross-border operation into Laos to interdict the Ho Chi Minh Trail and destroy the North Vietnamese supply dumps in the area.

Although the only direct U.S. support permitted was long-range cross-border artillery fire from firebases in South Vietnam, fixed-wind air strikes, and 2,600 helicopters to airlift Saigon troops and supplies, President Richard Nixon's critics condemned the invasion. Foreign Relations Committee chairman Senator J. William Fulbright (D-Arkansas) declared the Laotian invasion illegal under the terms of the repeal of the Gulf of Tonkin Resolution, which allowed the president only the mandate to end the war.

1972 U.S. troops fight biggest battle in nearly a year.

U.S. troops clash with North Vietnamese forces in a major battle 42 miles east of Saigon, the biggest single U.S. engagement with an enemy force in nearly a year. The five-hour action around a communist bunker line resulted in four dead and 47 wounded, almost half the U.S. weekly casualties

1968 Mass graves discovered in Hue

Allied troops who had recaptured the imperial capital of Hue from the North Vietnamese during the Tet Offensive discover the first mass graves in Hue.

It was discovered that communist troops who had held the city for 25 days had massacred about 2,800 civilians whom they had identified as sympathizers with the government in Saigon. One authority estimated that communists might have killed as many as 5,700 people in Hue.

The Tet Offensive had begun at dawn on the first day of the Tet holiday truce (January 30), when Viet Cong forces, supported by large numbers of North Vietnamese troops, launched the largest and best coordinated offensive of the war. During the attack, they drove into the center of South Vietnam's seven largest cities and attacked 30 provincial capitals ranging from the Delta to the DMZ. Among the cities taken during the first four days of the offensive were Hue, Dalat, Kontum, and Quang Tri; in the north, all five provincial capitals were overrun. At the same time, enemy forces shelled numerous allied airfields and bases. By February 10, the offensive was largely crushed, but resulted in heavy casualties on both sides.

1965 First South Korean troops arrive

The first contingent of South Korean troops arrives in Saigon. Although assigned to non-combat duties, they came under fire on April 3. The South Korean contingent was part of the Free World Military Forces, an effort by President Lyndon B. Johnson to enlist allies for the United States and South Vietnam. By securing support from other nations, Johnson hoped to build an international consensus behind his policies in Vietnam. The effort was also known as the "many flags" program. By the close of 1969, there were over 47,800 Korean soldiers actively involved in combat operations in South Vietnam. Seoul began to withdraw its troops in February 1972.

1962 Diem survives coup attempt

South Vietnamese President Ngo Dinh Diem survives another coup attempt when Republic of Vietnam Air Force pilots Lieutenants Pham Phu Quoc and Nguyen Van Cu try to kill him and his brother Ngo Dinh Nhu by bombing and strafing the presidential palace.

Lieutenant Quoc was arrested after his fighter-bomber crash-landed near Saigon. Lieutenant Cu fled to Cambodia, where he remained until November 1963. The attack confirmed Diem's conviction that his main adversaries were domestic. As a result, he retreated deeper into himself, delegating more authority to his brother Nhu, who set about eradicating dissidents--dozens of Diem political opponents disappeared, and thousands more were sent to prison camps. Diem and his brother were killed during a coup in November 1963.

1965 United States assails North Vietnamese "aggression"

The U.S. State Department releases a 14,000-word report entitled "Aggression from the North--The Record of North Vietnam's Campaign to Conquer South Vietnam." Citing "massive evidence," including testimony of North Vietnamese soldiers who had defected or been captured in South Vietnam, the document claimed that nearly 20,000 Viet Cong military and technical personnel had entered South Vietnam through the "infiltration pipeline" from the North. The report maintained that the infiltrators remained under military command from Hanoi. The Johnson administration was making the case that the war in Vietnam was not an internal insurgency, but rather an invasion of South Vietnam by North Vietnamese forces. This approach was a calculated ploy by President Lyndon Johnson, who realized that he would have a hard time convincing the American public that the United States should get involved in a civil war--acting to stop the spread of communism by invading North Vietnamese would provide a much better justification for increased U.S. involvement in the conflict.

1969 Communist offensive continues

Communist forces shell 30 military installations and nine towns in South Vietnam, in what becomes known as the "Post-Tet Offensive." U.S. sources in Saigon put American losses in this latest offensive at between 250 and 300, compared with enemy casualties totaling 5,300. South Vietnamese officials report 200 civilians killed and 12,700 made homeless.