Those who advocate "Buy American' should look around his/her own household and find stuff that were made in USA. Try buy a TV made in US. You will have a field day. For example, Vizio is an US brand (sold mainly at Costco), but they source LCD panels, parts from Taiwan and Korea. Some, if not all, were made in these two countries.
So, "buy American". Tell me how to tell. Most Americans would love to do that if they could actually tell and be convinced.
It is almost to the point now that every consumer product we buy is made overseas. This idea of a "world economy" has cost us (USA) dearly, instead of "lifting" up the world economy to our levels we are "sinking" down to theirs. We have sent our industries and jobs overseas and at the same time leveraged ourselves to the edge of oblivion.