Parliament adjourned on November 14, 1941, and was not scheduled to return until January 21, 1942. At the urging of the Soviet Union, the United Kingdom declared war on Finland on December 6, 1941. At the UK's urging, the Canadian Cabinet the next day issued a proclamation declaring war on Finland, Hungary, and Romania.
On December 7, 1941 (December 8 in Japan), the Empire of Japan began an undeclared war upon the United Kingdom (invading Hong Kong and Malaya), Canada, and the United States (attacking Pearl Harbor). Mackenzie King and the Cabinet decided to go to war with Japan that evening and issued a proclamation the following day declaring that, as of December 7, a state of war existed between Japan and Canada. That same day, the US and UK also declared war on the Japanese Empire. These proclamations were presented by Mackenzie King to the House of Commons when parliament returned on January 21, 1942.