Question

What would happen politically if the United States withdrew from the world and retracted into complete isolatism?

Answer 1

mmm. speculation. I like it. Time for random thoughts on the topic.
Our economy would collapse. No foreign markets to sell to.
Russia, China and India would fight it out for world domination. Europe could do it but they never seem to get along together for very long.
World economy would tank. Dictators and such would take advantage of that all over the world.
We'd kill each other off. Thin the herd, so to speak. With a terrible economy life would get miserable real fast. Basic values of human rights and equality would go out the window in most urban places.
New York city, New Orleans, Losangles and all other port cities would go in to chaos. No jobs there.
Other countries would attack us at an ever increasing rate and with ever increasing force. For our resources if nothing else.

Mostly this would be a bad idea. It's just not how America works.