Buy American what? Which items are manufactured domestically in sufficient quantities to satisfy American consumer demand?
Given a climate that is hostile to business development (thanks to high-labor-cost unions and a government that over-taxes and over-regulates), which manufacturers would be foolish enough to move their operations back to the US?
Manufacturing will (immediately) re-appear as if by magic, if we simply implement across-the-board import tariffs.
If import tariffs are raised precisely to the point at which it becomes slightly more cost efficient to produce and sell here, than to fire Americans.
We will see the true, invisible hand of the marketplace perform simple magic. Right in front of our eyes.
America first.