Why did that us become a military power?

Answer 1

America became a military power thanks in part to its location. It rarely faced invasion as it was separated from the rest of the world by two huge oceans, so despite being weak at first, it had the incredible resources and little distraction to build up its infrastructure and military. It also only has two border countries, Canada and Mexico to deal with. But ultimately, it was World War II that made America powerful. As I said before, the two oceans, Pacific and Atlantic, prevents attack from its enemies, in this case the Germans and Japanese. So America was able to easily convert its industry and build up its military without distraction from bombs and raids. The original tiny prewar size of the military was increased many times over and after the war ended, America transformed from a neutral isolationalist nation into a major player in the world stage.