Before the Japanese bombed Pearl Harbor, many Americans were undecided (and against) our nation getting involved in another war in Europe. However, the surprise attack in Hawaii solidified the nation's resolve to join England in its fight against Germany and Japan and their allies. The British were well aware that once America brought its massive military and financial reserves into action that it was only a matter of time before Germany and Japan succumbed to overwhelming numbers. Germany's attack on their former allies, the Russians, brought Russia into alliance with the U.S. and Great Britain, providing another nation capable of supplying huge armies to attack Germany from the north. Once the D-Day Invasion succeeded, the plan was to defeat the Germans and Japanese by sea and air as well as on land. American naval superiority soon asserted itself in both the Atlantic and Pacific, and the once-mighty German Luftwaffe was also weakened significantly. Allied forces soon surrounded German armies from three sides, and Japan's military force eventually withdrew back to its home islands to brace for the expected Allied invasion.