World War II April 1940, and the following month the army and the Luftwaffe (air force) invaded and took control of the Netherlands, Belgium, and Luxembourg The French had depended on the impregnable line of fortifications known as the Maginot line for protection against a German attack, but the latter avoided it and advanced into France through Ardennes in June The triumphant Nazi army entered Paris on June 14 An armistice was signed on June 22, and Marshal Henri-Philippe Pétain (1856–1951) became the premier of the puppet Vichy government General Charles de Gaulle (1890–1970) organized the Free French government in exile, and Britain recognized it on June 28 A resistance movement against the Nazis also developed among exiles from Poland, Norway, the Netherlands, Yugoslavia, Belgium, and other countries The German air force began to attack military installations in the south of Great Britain and in September began to bomb London and other cities In the Battle of Britain, from August to October, the Royal Air Force held against the Luftwaffe The Tripartite, or Axis, pact was signed between Germany, Italy, and Japan JAPAN MOVES FORWARD Japan, like its Axis partners, had followed an aggressive foreign policy Militarism was in ascendancy in the country The era of acquiescence of the Paris conference and the Washington agreements was coming to an end The extension of naval disarmament to cruisers, destroyers, and submarines at the London conference of 1930 was disliked by the army and the extreme rightists An agenda of military expansion and territorial acquisition was in the offing From the 1930s the military acted as a force above the law, and there were a series of political assassinations of Japanese politicians by army officers The issue between Japan and China that began over the Manchurian incident propelled Japan toward the war Manchuria would be a prized possession because its abundance of iron and coal could provide raw materials to the Japanese heavy industries The vast land area could also solve to an extent the problem of overpopulation In September 1931 the Japanese Kwantung Army marched unilaterally to occupy Manchuria The client state of Manchukuo (1932–45) was established The League of Nations had not done anything substantial to check the Japanese aggression Japan withdrew from the league in 1933 The second Sino-Japanese War began in July 1937 after a Japanese attack on five northern provinces in China The Nationalist capital, Nanjing (Nanking), was sacked with brutality Anti-Comintern 421 alliance and Japanese endorsement of German and Italian policies changed the situation Japan received full support from the two countries The Rome-Berlin-Tokyo Axis was formed after the Tripartite Pact, with the provision of political, economic, and military assistance in case of attack against a signatory by a country not involved in the present European or Sino-Japanese wars The provision obviously referred to the United States With the support of Germany and Italy, the Japanese war machine moved into Southeast Asia, incorporating it with the Greater East Asia Co-Prosperity Sphere Balkan countries like Hungary, Romania, and Bulgaria joined with the Axis powers on March 25, 1941 Greece and Yugoslavia capitulated to Axis control in April The Nazi plan of lebensraum had looked toward the east, and Operation Barbarossa against the Soviet Union began on June 22, with Hungary, Romania, Finland, and Bulgaria joining in Hitler was confident of a victory before the winter, and the Nazi blitzkrieg almost worked Troops reached Leningrad within three months, overrunning the Ukraine region and nearing Moscow But the Red Army fought back, and national spirit was high The winter set in, and the Soviet Union regained much ground Meanwhile, relations between Japan and the United States were taking a nosedive, which would result in a change in the course of the war The Allied powers would gain an upper hand The attack on Manchuria in 1931 and the second Sino-Japanese War, beginning in 1937, convinced the Unites States that Japan was on a mission to dominate the Far East The Japanese were ready to invade the Dutch East Indies The United States demanded the withdrawal of Japanese troops from China and Southeast Asia Japan countered with a proposal that the United States should not interfere with the government set up in Nanjing After the beginning of World War II, Washington had followed a policy of pro-Allied neutrality and was involved in the war through the Lend-Lease program It was also fully prepared in case it was forced to join the war U.S president Franklin D Roosevelt (1882–1945) had called a special session of Congress in September 1939 and revised the neutrality laws British premier Winston Churchill (1874–1965) met Roosevelt on August 14, 1941, and both signed the Atlantic Charter, which called for international peace Negotiations between the Japanese government, headed by Tojo Hideki (1884–1948), and Roosevelt were not successful The Japanese attack was imminent, but the United States was in the dark about where the Japanese would strike The assumption was that it would be in