Between 1969-1975, what key events happened in the Vietnam War?

May 1961: President John F. Kennedy sends helicopters and 400 Green Berets to South Vietnam and authorizes secret operations against the Viet Cong.

November 1963: President Kennedy is assassinated in Dallas, Texas. Lyndon B. Johnson becomes president.

February 1965: President Johnson orders the bombing of targets in North Vietnam in Operation Flaming Dart in retaliation for a Viet Cong raid at the U. S. base in the city of Pleiku and at a nearby helicopter base at Camp Holloway.

July 1965: President Johnson calls for 50,000 more ground troops to be sent to Vietnam, increasing the draft to 35,000 each month.

1966: U. S. troop numbers in Vietnam rise to 400,000. 1967: U. S. troop numbers stationed in Vietnam increase to 500,000.

February 1967: U. S. aircraft bomb Haiphong Harbor and North Vietnamese airfields.

March 1968: President Johnson halts bombing in Vietnam north of the 20th parallel.

November 1968: Republican Richard M. Nixon wins the U. S. presidential elections on the campaign promises to restore "law and order" and to end the draft.

December 1972: President Nixon orders the launch of the most intense air offense of the war in Operation Linebacker.