Neville Chamberlain, the Conservative politician, was prime minister from 1937-40. When Baldwin retired in 1937, Chamberlain was his natural successor. By then there was a single dominant issue in world affairs — the aggressive intentions of Nazi Germany. The majority in Britain hoped that a peaceful solution could be found for Germany's claims on areas of other countries with German populations, and Chamberlain was a willing spokesman for this policy of appeasement. With the agreement at Munich in 1938 he effectively abandoned Czechoslovakia, but immediately accelerated Britain's rearmament program and the following year declared that Britain would defend Poland. This commitment led, in September 1939, to the start of World War II. He brought into his war cabinet the leading opponent of appeasement, Winston Churchill. The failure of the campaign in Norway in April 1940 led to his resignation, being succeeded by Churchill.