I try and think long-term. In the long-term trading blocs will develop such that they consist of the countries with the lowest trade barriers with each other. These blocs will thrive while those with more trade barriers will be relatively less prosperous.
I guarantee that a more protectionist US will lead to most of the world’s nations looking to make trade deals with the EU (which will be Muslim in a few generations). Then EU goes up in power and America goes down in power. Note that China will look to the EU more as well.