But now that protectionism is a trivial issue, what will economists inveigh against?
I can't speak about the younger generation of The Econ, but when I was still among them economists spent a reasonable amount of time teaching their students about the evils of policies that barely existed anymore. On the whole, academic economists are probably more liberal than people think (understandably because the public face of academic economists isn't very liberal), but the things "everybody" agreed about were things like free trade good, rent control bad, etc.