The Thai took great pride in their nation's status as the lone independent state in Southeast Asia, so most resented the uninvited arrival of Japanese troops. The nation's leaders were dismayed, too, but painfully aware of the futility of resistance. Some doubted the wisdom of Phibun's decision to embrace Japan fully, however, anticipating that the Allies would prevail in the end. In such an eventuality, they knew that Thailand would be in dire straits if it remained yoked to a defeated Japan.

From 8 December 1941, these skeptics looked to Phibun Songkhram's chief political rival Pridi Phanomyong, who had served as interior minister, foreign minister, and finance minister in successive cabinets, for leadership. Pridi, resentful of the growing army dominance in Thai politics, had responded to Phibun's tilt toward Japan and the Axis Powers by moving toward a pro-British stance even before the war began. Because the Japanese were suspicious of Pridi, Phibun relieved him of the finance portfolio in mid-December 1941, softening the blow by appointing him to the prestigious, but politically impotent, Council of Regents that acted for the nation's absent monarch, the teenaged King Ananda.

Phibun and his supporters saw full cooperation with Japan as the best course available, but were well aware of the risks. As a Thai police officer pointed out to an interned British civilian, if the Japanese won the war they would be in a position to dominate Thailand totally.