Why did the united states assert itself as a world power?

Well this is an opiniated question but I can give you some of the possibilities:

- Nationalism ( many countries have this trait). Usually the more you have the more of a world power you can become.

- To make a statement. To gain attention for the cause they believe in and to persuade or influence the rest of the world.

- During World War 2 the USA had officially become a world power and this is because they fought back and proved they could defend the weak who were also being attacked.

Please vote my answer brainliest. thanks!