Yeah, it would cost some jobs, but would create more. Trade barriers protect jobs within favored industries, but they invariably lose more jobs elsewhere in the total economy than they protect. Look at the steel tarrifs. In order to protect, what is it, about 30,000 jobs in the steel production industry, many thousands MORE jobs in industries that use steel as a raw material (auto production, appliances, steel drum mfg, etc, etc, etc) are being threatened. In order that we buy less steel from overseas, everything we export that uses steel in its manufacture becomes dramatically less competitive. This is a general phenomena. Artifically reducing your imports hurts your exports as much or more.
...and depresses wages (overall more than wages in poltically favored and therefore protected industries are raised), and raises the cost of living for everybody.
I understand your point. However, if most of the steel industry goes overseas and we need to build a military machine in order to fight some war, we may end up with the same problem of treading on eggshells that we have with the countries we buy oil from.