World War II
Explanation:
The US was already a regional power and a economic power following the Spanish American War, which saw to the US taking Philippines as well as Cuba from Spain. They also helped liberate Panama from their neighbor Colombia, who then gave the US the right to build and lease the Panama Canal, furthering expanding the US imperial reach through the connection of the two navies (Pacific & Atlantic). The disposing of Queen Liliuokalani by US settlers soon added Hawaii as a US colony, which later became a state. The US also previously owned Alaska, after buying "Seward's Folly" from Imperial Russia. This set up the stage for the US to become a Industrial Power.
Following the event of the start of World War II, the US turned it's large industrial power into creating war material for the Allies. They soon joined the war with the Attack on Pearl Harbor on Dec. 7, 1941, commonly known as "the Day that will live in Infamy", coined by the desist Franklin D. Roosevelt. Following the Industrial build-up, the US soon turned it's attention to creating what is known as Military Super Power, spending trillions of dollars each year to create one of the most technological army in the world.
At that is what leads us to where we are today. However, deficit Democratic leadership had previously broken down the US military might as well as disorient original US values, and so the US has lost some of it's rights to being the World's only Super Power, or the "Overseer".
All in all, the US was able to rise to become a super power due to location, chance, and the actions they took to insure the best results for themselves. Whether the US can continue to do so in the future, is up to the citizens to decide.
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