Final answer:
The US and its allies employed a 'Europe First' strategy, prioritizing the defeat of Germany and Italy, which eventually led to the invasion of France on D-Day.
Step-by-step explanation:
The military strategies employed by the United States and its allies to defeat the Axis Powers in World War II were complex and multifaceted. The key strategic approach adopted was the 'Europe First' strategy, which prioritized the defeat of Germany and Italy while maintaining a defensive stance against Japan. In the European theater, this involved invasions of North Africa and Italy, building up to the pivotal cross-channel invasion of Europe via France in 1944, known as D-Day. This strategy was combined with consistent diplomatic efforts, as exemplified by conferences such as the one in Yalta in February 1945, to coordinate Allied efforts and attain consensus on post-war plans.
In the Pacific Theater, the United States adopted an 'island-hopping' strategy. This involved attacking and capturing key islands, getting progressively closer to Japan. This approach was critical in turning the tide against a series of early Japanese victories. Aircraft carriers and the securing of airfields were crucial in this strategy, as they provided the means to project power over vast distances and support amphibious landings. The culmination of the Pacific campaign was the controversial decision by President Truman to employ atomic bombs against the cities of Hiroshima and Nagasaki, leading to Japan's surrender and the end of the war.
Throughout the conflict, the Allies experienced a series of turning point victories from 1942 onward, leading to a reversal of Axis successes and securing the overall victory for the United States and its partners. This was achieved despite initial setbacks and the challenges posed by the global span of the war.