a civil war between the Communist-dominated (and Hanoi-directed) Pathet Lao, neutralists, and American-backed rightists, included provisions that required the removal of all foreign military forces and precluded the use of Lao territory for interfering in the internal affairs of another country – a blatant effort to shut down North Vietnam's growing logistical corridor through southeastern Laos that would become known as the Ho Chi Minh Trail. A coalition Government of National Union was installed in the capital of Vientiane, but it soon ran into difficulties. By the 2 October 1962 deadline for the removal of foreign troops, the North Vietnamese had pulled out only 40 personnel, leaving approximately 6,000 troops in the eastern half of the country. Meanwhile, rightist elements (in control of the army) opposed the new government. The U.S. played its part by increasing its assistance to the right by covertly supplying the army through Thailand. Despite another international accord, Laos remained ensnared by the political and territorial ambitions of communist neighbors, the security concerns of Thailand and the United States, and geographic fate. Fighting soon erupted between elements of the Pathet Lao and the Royal Lao Army. Although tentative negotiations resumed between the factions, matters took a turn for the worse when neutralist Prime Minister Prince Souvanna Phouma was arrested during a right-wing coup attempt. U.S. Ambassador Leonard S. Unger then notified the generals that the U.S. government would continue to support Souvanna. This turn of events had a profound effect on Laotian politics: First, it affirmed American support for Souvannah, only a few years after the U.S. had denounced him as a tool of the leftists; It also caused the neutralists to shift political allies from the left to the right; Finally, in May 1964, Souvannah announced the political union of the rightists and neutralists against the left. Heavy fighting broke out on the Plain of Jars as the members of each political grouping chose sides. Souvanna called upon the U.S. for support and was answered in the affirmative by President Lyndon B. Johnson, who was eager to support a rightist/neutralist alliance in Laos. In November 1963 General Maxwell D. Taylor, chairman of the Joint Chiefs of Staff had proposed that U.S. armed reconnaissance missions be conducted over Laos as part of a two phase program that would warn Hanoi of U.S. determination to support the Saigon government. The missions were to take place along North