Yes, we have all the necessary requirements for a self-sufficient nation.
No, our ties to the globe are too strong, the United States can never regress into it's isolationist days.
It doesn't have to be all at once, can be done gradually, providing time to decrease dependency on foreign oil. At the least, our country needs to start being a lot more selective in it's global interactions. Trading would always be allowed, provided we don't depend on the product, so we could cease at any time necessary.
We could do it, but we would eventually just become like North Korea, Ultimately world trade greatly helps a nations economy.
Only the government and the special interest groups that control it prevent us from exploiting our mineral, land and petroleum resources correctly and efficiently as would happen in a free market. We could in fact be ten times more powerful than China and hold trade CREDIT instead of debt if only it were financially viable for companies to manufacture, mine, invest, drill, and farm in the U.S. more than it does. Made in China = Made in A More Attractive Business Market.
Theoretically it is possible, but realistically it isn't likely. For instance, even at our current oil production levels we can only supply about 50% of our consumption. We get an additional 30% from Canada and 12% from Venezuela. The last 8% come from the middle east. It is possible by 2030 to be dependent on only American (the continents) resources, but not just the US.
America relies heavily on the H-1B visa. Get rid of that - and America will collapse.