Reality check. You are on the World Wide Web right now. Reality Check, your PC, car and basically everything else you use is built by companies that have interest world wide. You think that is going away? If so shut down you PC and mail in your comments.
We have invented or developed basically every advance the world has known. We few people (302 Million of us) constitute the largest single national economy, in large part due to our role as a world player. The economies under us such as Japan are economies we created. Playing in the global economy is different then a one world government. You have to separate global political movements from global economic ones. Which is where the problem lies. Sovereignty yes, isolationism no. The liberal bent for "we are the world, let's hug" is riding the peoples desire for new products and the free markets desire for competitive labor
You want to place blame for why this is not working out currently then blame the unions who price our labor out of sight, blame the bad management who can’t control spending, but that is no reason to call it quits. That would destroy us either directly because our economy would collapse, or in the long run when the Chinese, Russians and EU see us ripe for the pickings because they have had a chance to catch up in technology and build up in strength and we have a lot of resources. I am as patriotic as the next guy but there is no way even if we armed the whole country we could beat that short of a nuclear exchange, then who would give a damn about liberalism, conservatism or any ism since there would be none.
Lock down the boarder, deal with the hand we let the politicians deal us and keep us out there as a global force, albeit in a better manner than we approach it now, so that we set the tone of global affairs as much as possible. Preferable the US government that does that is a conservative but realistic one. This is the 21st Century, not the 19th.