Ironically enough, back in the latter 19th and early 20th century, the Republicans tended to be the more protectionist of the two parties. The infamous Messrs. Hawley and Smoot were both Republicans.Trump is more radical left when it comes to Tariffs. Even Woodrow Wilson would be like "dude slow down". Certainly not the party of Reagan anymore that's for sure.
So, in some sense, they've returned to their roots.