When doesnt America try to take over everything?
Let's break this down into categories:
Global Political - We successfully avoided the rest of the world, after achieving freedom, until ww1 when our buttons were poked too much. Then we retracted only for the world to go so far down the drain that a country had a dumb enough idea to awake the sleeping giant. So we tried to be isolationist, but when we don't get involved everyone blows each other up and sometimes us. I think most Americans, even from both political parties, would love if we could go back to isolationist. But you know what would happen? China and North Korea would over run South Korea and Japan. Russia would take a whole lot more than Crimea. There would be Islamic terror groups all over Middle East and Africa butchering anyone who wasn't their specific sect of Islam, there would be drug cartels and communist repression all over South America. Yeah we screw up but the world (and our own American safety) would be in shambles if we just isolated ourselves again.
Economics - Europe depleted many of its natural resources on wars for thousands of years, as did Asia to an extent. Africa fell way behind in technology and never had empire building nations (even Zulu wasn't on par with European nations). America's rapid expansion from sea to sea allowed control over vast untapped resources. It is only fitting we are the global powerhouse we are now economically speaking as our resources are less depleted. We also were able to industrialize without facing constant invasion like the rest of the world due to ocean walls.
Cultural - When you dominate the first two, this tends to follow.
The funny part is, we are nowhere near dominate compared to the Statue of Nebuchadnezzar empires (Babylonians, Persian/Medes, Macedonians, and Romans). We have China and (used to have) USSR going toe to toe with us, those other nations made jokes of everyone else until their final years.