In the summer of 1940, Adolf Hitler launched Operation “Sea-Lion”, or better known as the Battle of Britain. This was a plot to destroy the British RAF in order to enable a German landing on the beaches of England and an air assault. Due to the failure of the Battle of Britain campaign, the tide of the war changed in favor of the Allies and Hitler's plan for European domination was halted. The early stages of the war were dominated by Germany, attacking Europe in rapid succession. Ground forces quickly overwhelmed European nations with aircraft support. The Luftwaffe quickly acquired air superiority. In early May 1940, Norwegian debates began to question the competence of the current British Prime Minister, Neville Chamberlain. On May 10, 1940, Germany invaded France and on the same day, Winston Churchill became the new British Prime Minister. Churchill's first course of action was to send support to the forces in France. He therefore sent poorly trained squadrons to France, although he had objections from RAF Commander Hugh Dowding. The superiority of Luftwaffe pilots proved fatal for the squadrons in France. Adolf Hitler was so confident that he could negotiate peace with Britain that he never planned an amphibious landing. However, on July 11, the great commander of the German navy, Erich Raeder, told Hitler that an amphibious landing on Britain was a last resort. It was planned that the invasion force would depart from bases in France, cross the English Channel and land on British soil. But it soon became clear that the British Royal Navy was still a force to be reckoned with. The only way to ensure the safe passage of the landing force was to use slow-moving heavy bombers and dive bombers to destroy the ships. And the only way, middle of paper, he reassigned the crews to the Eastern Front. In doing so, he effectively ended Operation “Sea-lion”. The effects of the entire campaign changed the entire perspective of the course of the war. For the British, this shows the courage of the British people: when threatened, they stand up and fight. It also changed the way Germany viewed Britain as an enemy. This battle showed them that Britain was no pushover and that they should be treated with caution. The battle also changed Americans' views. During the battle, many believed that Britain could not survive a prolonged fight against German power. However, after the battle, Theodore Roosevelt sought a second opinion. So he sent a United States ambassador on a short trip to Britain. Roosevelt became convinced that the nation could survive and that it must be supported.