In January 1942, as World War II intensified in the Pacific Theater, Allied air forces initiated a series of bombing raids on strategic locations in Southeast Asia, including Bangkok, Thailand. The city was of significant military and logistical importance, as Thailand had entered into an alliance with Japan following the latter's invasion. The bombardment aimed to disrupt Japanese operations and strengthen the Allies' position in the region. The attacks resulted in considerable damage and were a show of force intended to weaken Japanese influence in Thailand, which had become a crucial point for Japanese military supply lines.

In response to the Allied bombardment, the Thai government, led by Prime Minister Plaek Phibunsongkhram, reacted by declaring war against the United States and the United Kingdom. This decision illustrated Thailand's precarious position during the war, caught between its commitment to Japan and the pressures exerted by the advancing Allies. Although Thailand was officially an ally of Japan, public sentiment and some segments of the government began to lean toward the Allies as the war progressed and the realities of the conflict shifted.

The declaration was significant not just for Thailand's wartime stance but also for the complex dynamics of international relations in the region. Thailand's alignment with Japan had initially been a strategic move, but as the Allies began to gain the upper hand, the Thai leadership grappled with the consequences of their choices. This period marked a turning point in Thailand's involvement in World War II, as the nation sought to navigate its future amid the escalating conflict and the shifting allegiances of the global powers involved.