World War II began in September 1939 with Germany's invasion of Poland, as France and Britain declared war in response. Western leaders were stunned when the Soviet Union and Germany split control of Poland; the two powers had reached a non-aggression pact in August 1939, which contained a secret protocol for the partition of Poland. Though few Americans wanted to intervene in the war, an October 1939 Gallup poll showed that over 80 percent of the country favored Britain and France over Germany. Per the terms of the Neutrality Act, Roosevelt recognized a state of war in Europe, imposing an arms embargo on France, Britain, and Germany. Days later, Roosevelt called Congress into a special session to revise the Neutrality Act. Overcoming the opposition of famous aviator Charles Lindbergh and other isolationists, Roosevelt won passage of the Neutrality Act of 1939, which allowed belligerents to purchase aircraft and other combat material from the United States, albeit only on a cash and carry basis. Though the United States would remain officially neutral until December 1941, Roosevelt continued to seek ways to assist Britain and France.