Trump doesn't give a damn about breaking any international trade rules - he's promising to 'rip up' those treaties anyway the day he's sworn in.

But you're right - what our government should be doing is coordinating responses with other countries.  If the Americans want to be isolationist, we can't change that. But we can hedge by putting together deals with anyone else willing to make them. The going terms should be complete zeroing of tariffs, and none of the poison pill intellectual property and investor-state dispute liability clauses the US like to leverage into any deal they're part of.

Isolationism ultimately leads to depressions - only way for the rest of the world to minimize their exposure to the coming US disaster is freer trade amongst the rest of us. And if it becomes necessary to retaliate with tariffs on America's exports, non-US countries are going to have to stick together.