Canadians were all the more preoccupied with domestic economic problems and chose to remain neutral throughout the 1930s. Japan's invasion of Manchuria raised little concern in Canada, as did Hitler's rise to power in 1933 or Italy's invasion of Ethiopia in 1935. The Canadian government declared its neutrality on the outbreak of the Spanish Civil War in 1936 where Francisco Franco lead a military uprising, supported with military hardware and tens of thousands of troops by Nazi Germany and Fascist Italy against the legitimate Spanish government. Nevertheless, many Canadians volunteered to fight for the Spanish Republic in the International Brigades and couldn't be deterred by the Foreign Enlistment Act of 1937, outlawing participation by Canadians in foreign wars. Eventually, 1,546 Canadians participated, mainly in the Mackenzie-Papineau Battalion (also called "Mac-Paps") of which 721 were killed. Except for France, no other country gave as great a proportion of its population as volunteers in Spain than Canada.