The coup in 1977 was different. While other coups were staged to enhance military rule, this intervention was intended to allow greater democratisation, with the promulgation of a democratic constitution, elections to a House of Representatives, and the granting of political freedoms. The coup occurred a year after the military had seized power from the civilian government in a volatile political situation created by a series of clashes between left- and right-wing groups. The civilian government emerged from an uprising in 1973 which overthrew military rule, but the government could not cope with the political violence and internal bickering in the government parties, which characterised open politics. The seizure of power by the military in 1976 terminated the three-year period of the civilian regime and installed an ultra-rightist civilian government under the supervision of a military junta. The new government lasted only one year before being ousted by the same group of military leaders who had installed it.

One of the major reasons for the military staging the 1977 coup was the political suppression practised by the government. Most liberal and progressive groups were labelled communists or communist sympathisers and severely suppressed. A number had to flee to the jungles, where they joined the Communist Party of Thailand. Military leaders came under pressure from various groups in the civil society, and from a powerful faction in the army which could not tolerate this ultra-rightist policy, to replace the government with a more liberal one.

Following the 1977 coup parliamentary rule lasted almost twelve years, the longest period of civilian rule since 1932 (though the government survived two attempted coups). Political parties gained strength and legitimacy. Commitment to democracy among the educated Thai was on the rise and the military seemed close to accepting democratic norms and practices (Boonprasert 1990).

In February 1991, however, the military staged another coup, putting an end to parliamentary rule. Like the coups in 1947 and 1976, the military justified the intervention in terms of the weakness of the civilian government. It also cited the excessive corruption of civilian politicians, which had clearly undermined the legitimacy of the government. But the real reason behind the coup was the mutual distrust between the military and the government. A number of leading military officers felt insecure when Prime Minister Chatichai appointed ex-army chief General Arthit Kamlangek as deputy Defense minister in early 1991 to tighten control over the armed forces (Bunbongkarn 1992:132-33).

Prime Minister Chatichai came to power in 1989 after General Prem declined an invitation to continue in the premiership. As the leader of the biggest party in the National Assembly after the 1989 general election, Chatichai was the only legitimate successor to General Prem. He had maintained good relations with the military until the second year of his term, but his intention to exert more control over the military caused concern in the armed forces.

After the coup, the military was faced with a problem of how to deal with the growing democratic forces. Protests led by pro-democracy parties, student organisations, and other civic groups against the draft constitution signified the growing commitment to democracy within those groups and forced the coup leaders to grant concessions (such as agreeing not to let active military officers hold political posts).