I'm probably wrong about all this, but methinks he mis-reads Trump.
-Roger Lowenstein, from here
A quick review of history shows Lowenstein is likely correct about tariff wars being bad from an economic perspective. But....it looks to me that Trump is using his willingness to unilaterally impose tariffs - on our allies as well as our foes - to get his way in international politics. Economics has nothing to do with it. But, I'm probably wrong.