The US threat of a trade war is the dumbest possible response to U.S President

The US threat of a trade war is the  dumbest possible response to President Trump's  threat of tariffs. Bragging is not an effective diplomatic tool. 

Three-quarters of our exports go  to the South. The US economy is ten times larger than ours and  is less dependent on trade than we are.
A trade war would be bad for the  US economy, but it would be  disastrous for us and would solve nothing.  The smart thing to do  would be to  the benefit  of the  United States and Canada  to take strong action to control our borders and stop the flow of drugs and  immigrants in both directions. 
This has been stated by the premiers of Quebec,  Newfoundland and Labrador, Alberta and  Saskatchewan. Meanwhile, politicians in Ottawa and Toronto are flirting with  a trade  deal. Are there any  grown-up politicians in Ontario?
Source @Maxime Bernier