In October 1958, Sarit, recently returned from the United States where he had undergone extensive medical treatment, took over personal control of the government with the consent of Thanom, who resigned as prime minister. Sarit, who spoke of instilling "national discipline" in the country, justified his action on the grounds that Thailand’s various constitutional experiments had not succeeded in providing the stability needed for economic development. He outlawed political parties and jailed critics of the regime--teachers, students, labor leaders, journalists, and liberal parliamentarians. A dozen or more newspapers were closed.
In January 1960, Sarit decreed an interim constitution that provided for an appointed assembly to draft a new constitution, Thailand’s eighth since 1932. Work on the document continued throughout the 1960s. Sarit assumed the office of prime minister provided for in the interim constitution, but his regime was clearly that of a military dictatorship.
Whatever else might be said about its political shortcomings, Sarit’s government was more dynamic than the previous regimes of the constitutional era. Sarit gave ministers in his cabinet considerable independence in the affairs of their own ministries. At the same time he made all major decisions and kept members of the government responsible solely to his office.
Despite recurring scandals involving official corruption, in the early 1960s Sarit seemed to have succeeded in achieving political stability and economic growth. In 1961 the government instituted the first in a series of economic development schemes that were intended to foster employment and expand production. Although military officers were frequently appointed as directors of state and quasi-governmental economic enterprises, civilian personnel gradually assumed a greater share in implementing government policies. Sarit welcomed foreign investment and assured investors of government protection. Major electrification and irrigation projects began, with aid from the United States and international agencies. In addition, Sarit initiated a cleanup campaign to improve sanitation in the cities.
Sarit revived the motto "Nation-Religion-King" as a fighting political slogan for his regime, which he characterized as combining the paternalism of the ancient Thai state and the benevolent ideals of Buddhism. He spoke of his intention to "restore" the king, a retiring man, to active participation in national life, and he urged Bhumibol Adulyadej and his consort, Queen Sirikit, to have more contact with the Thai public, which had a strong affection for the monarchy. Royal tours were also scheduled for the king and queen to represent Thailand abroad. Sarit likewise played on the religious attachments of the people. In 1962 he centralized administration of monastic institutions under a superior patriarchate friendly to the regime, and he mobilized monks, especially in the North and Northeast, to support government programs. Critics protested that Sarit had demeaned religion by using it for political ends and had compromised the monarchy by using it to legitimize a military dictatorship. They asserted that the regime’s policies, rather than restoring these institutions, had contributed to the growth of materialism and secularism and to the erosion of religious belief in the country.
Under Sarit’s guidance, Thailand’s anticommunist policy continued, and steps were taken to deal militarily with the growing threat of insurgency posed by communist-inspired activities in neighboring countries. Sarit sought closer ties with Thailand’s anticommunist neighbors and with the United States, and in 1961 Thailand and another SEATO member, the Philippines, joined with newly independent Malaya (since 1963, Malaysia) to form the Association of Southeast Asia (ASA). The Pathet Lao (as the leftist Lao People’s Liberation Army was known until 1965) moved into northwestern Laos in March 1962. United States secretary of state Dean Rusk and Thai foreign minister Thanat Khoman agreed that their countries would interpret the Southeast Asia Collective Defense Treaty of 1954 as a bilateral as well as multilateral pact binding the United States to come to the aid of Thailand in time of need, with or without the agreement of the other signers of the pact. Two months after the foreign ministers’ agreement, President John F. Kennedy stationed United States troops in Thailand in response to the deteriorating situation in Laos. The arrival of the troops in May 1962 was seen by the Thai government as evidence of the United States commitment to preserving Thailand’s independence and integrity against communist expansion. Despite United States pressure, however, Sarit refused to entertain ideas of democratic reform.