President Lyndon B. Johnson's March 1968 announcement that the United States would halt bombing in North Vietnam and seek a negotiated settlement came as a blow to the Thai government, which had not been consulted on the change in policy. Although the defense of Thailand clearly remained essential to the security of Southeast Asia in United States strategic thinking, no provision was made for Laos, whose security the Thai saw as essential to their own defense.
While remaining loyal to its commitments, Thailand thereafter determined to restore flexibility to its foreign policy by moving away from one-sided dependence on the United States. The military, however, was anxious to continue Thailand's active involvement in South Vietnam and in Laos, where several thousand Thai "volunteers" were engaged against the Pathet Lao. Thanom urged United States backing for the Lon Nol regime in Cambodia in 1970 and proposed a formal alliance linking Thailand with Laos, Cambodia, and South Vietnam that would give the conflict in Southeast Asia the appearance of a war being fought by Asian anticommunists for Asian security. The plan failed to get United States support.
Communist activities in Laos and Malaya had already begun to affect the domestic situation in the South and the Northeast in the 1950s, and by the 1960s they presented a problem of increasing magnitude. Communist guerrillas, mostly ethnic Chinese, operated in jungle areas north of the Thai-Malayan border, where they had taken refuge from Commonwealth of Nations security forces during the 1948-60 Emergency in Malaya. A more serious threat in that same region were the Muslim insurgents of the Pattani National Liberation Front, a Thai separatist group composed of ethnic Malays. Meanwhile, in the northern provinces dissident Meo tribesmen reportedly had begun receiving training and arms from the Pathet Lao by 1950. In the Northeast, underground leftist parties took advantage of grievances over relatively poor economic and social conditions to rally opposition to the government. Faced with the problems in the South, North, and Northeast, the Bangkok government frequently identified regional unrest and protest against ethnic and economic policies with the genuine communist-based insurgencies that overlapped and often benefited from it. Opposition groups and critics of the regime in Bangkok were also generally labeled as communists.