Churchill became prime minister in 1940 after the failed Norway campaign weakened Chamberlain. Churchill initiated the Norway operation despite risks of bringing Germany in. This was criticized by historians as diverting resources and showing indecisiveness. Churchill's leadership style involved rousing speeches to boost morale. There was genuine fear of German invasion, but the navy likely could have defeated landings. The decision to send forces to North Africa showed bravery when the army was weakened after France. Churchill's contribution in 1940 rallying resistance was considered his "finest hour" and made the difference between defeat and survival for Britain.