It's not posturing. Trump has just added a 20% tariff on softwood lumber and so far we have not heard much of anything from Trudeau. The tariff is imposed retroactively 90-days starting today and lumber operations here are saying they will need immediate Gov't loans to help them pay that bill. Where is our Prime Minister?
CNN is now reporting Trump is seriously considering an executive order to pull out of NAFTA. 
It's time Justin put on his big boy pants and got to work.
And no, the tariff can be imposed without any court injunction. If we go to the WTO to launch an official complaint, it will take months before we get any decision.