Cause: Vietnamese resistance to French colonialism. Effect: Geneva Accords and division of Vietnam.

Cause: Alleged attacks on U.S. ships. Effect: Gulf of Tonkin Resolution and escalation of U.S. involvement.

Cause: U.S. strategy to weaken North Vietnam. Effect: Limited success, increased civilian casualties, and anti-war sentiment.

Cause: North Vietnamese attempt to incite rebellion in South Vietnam. Effect: Showed the war was far from over, decreased U.S. public support, and LBJ's decision not to run for reelection.

Cause: Frustration and anger among U.S. soldiers. Effect: Increased anti-war sentiment and damaged U.S. credibility.

Cause: Nixon's desire to reduce U.S. involvement. Effect: Gradual withdrawal of U.S. troops, but ultimately the collapse of South Vietnam.

Cause: Withdrawal of U.S. support and North Vietnamese offensive. Effect: Reunification of Vietnam under communist rule.

Cause: Fear of communism spreading in Southeast Asia. Effect: Justified U.S. intervention in Vietnam.

Cause: End of the First Indochina War. Effect: Temporary division of Vietnam and future conflict.

Cause: Growing anti-war sentiment and the Tet Offensive. Effect: Opened the door for Nixon's election and a shift in war strategy.

If South Vietnam fell to communism, other nations in Southeast Asia would follow.

It gave President Johnson broad authorization to use military force in Vietnam without a formal declaration of war.

A sustained aerial bombardment of North Vietnam by the U.S. military.

Nixon's policy of gradually withdrawing U.S. troops and transferring responsibility for the war to South Vietnam.

Nixon's stated goal of ending the Vietnam War in a way that preserved U.S. credibility.

A peace treaty between North Vietnam, South Vietnam, and the United States to end the Vietnam War.

South Vietnamese communist rebels who fought against the South Vietnamese government and the United States.

Asian allies would receive US support, but without the extensive use of U.S. ground forces.

A series of surprise attacks by the Vietcong and North Vietnamese forces during the Tet holiday in 1968.

It was the provisional military demarcation line between North and South Vietnam established by the Geneva Accords of 1954.

The communist leader of North Vietnam who fought for Vietnamese independence.

The leader of South Vietnam, supported by the U.S., but assassinated in 1963.

U.S. President who escalated the war following the Gulf of Tonkin incident.

U.S. President who implemented Vietnamization and negotiated the Paris Peace Accords.

Commander of U.S. forces in Vietnam who pursued a war of attrition.

U.S. officer convicted for his role in the My Lai Massacre.

CBS newscaster who turned against the war after the Tet Offensive.

U.S. President who articulated the domino theory and supported South Vietnam.

U.S. President who sent advisors to South Vietnam.

Defense Secretary who recommended sending 100,000 combat troops to Vietnam.