Operation Lam Son 719
Operation Lam Son 719 was the first major operation conducted by the Army of the Republic of Viet Nam without being teamed with American ground troops. Launched in 1971, it was intended to interdict areas of the Ho Chi Minh trail in Laos. It was a failure.
- 1st ARVN Infantry Division
- 1st ARVN Airborne Division
- 1st ARVN Ranger Group
- 1st ARVN Armored Brigade
GEN Creighton Abrams, commander of the U.S. Military Assistance Command, Vietnam, was frustrated when one starting date after another was missed. He asked Ted Shackley, the Central Intelligence Agency station chief in Saigon, to find out why the delays were happening, since the explanations he had received from ARVN did not make sense to him. Shackley was able to talk to III Corps tactical zone commander Do Cao Tri, with whom he had formed a good working relationship. Tri agreed that it was not the operational commander, LTG Lam that kept postponing, but President Thieu, whose astrologer told him that various proposed dates were inauspicious. Tri, who died in an operational helicopter crash a few weeks later, accepted a bribe to be given to Thieu's astrologer. Thieu was told that February 8, preferred by MACV, was auspicious, and the invasion finally launched on that day. 
The main combat support base was at Khe Sanh, where new runways had been constructed.
Before the retreat
At the beginning of April, U.S. Secretary of State William Rogers said that the operation would run through April, perhaps until the monsoon season started in early May. Following the attack of Tchepone, the troops had an option to swing southwest, attacked a road and base area, and returned back, striking through the stronghold in the A Shau valley.
In the attack on Tchepone, People's Army of Viet Nam (PAVN) communist forces caused high casualties at two points. According to Time, "As a general, Thieu saw that his troops, with reinforcements readied, could have held their own. As a politician, he was concerned about the effect back home of the possible high casualties." See Army of the Republic of Viet Nam motivation. Official ARVN estimates were 25% of the 25,000 man force, and unofficial went to 50%. The U.S., which had been providing the helicopter list, had 177 casualties and lost 94 helicopters.
The operation ends
At the regular MACV briefing, a usually polished spokesman said, "As of today no ARVN elements remain in Laos," he began. "Enemy forces are now chasing them toward the border—wait, I don't mean to use that word. They are following them to the border." Not only were they being pursued by PAVN soldiers in Soviet-built tanks, but in capture U.S. tanks as well.
PAVN movements in North Vietnam and the DMZ threatened a counterattack, invading South Vietnam. There were 20,000 PAVN troops north of the DMZ, with tanks and artillery in the DMZ itself. 20,000 ARVN and 15,000 U.S. ground troops were moved south of the DMZ.