Free trade based on the principle of comparative advantage only survives so long as the gains of free trade are adequately distributed to the public. Otherwise, the public will revolt and show the elites who's really in control, even if they don't end up better off in the short-medium term. In the long run, this can lead to reestablishment of free trade on more equal terms. The elites must preemptively make free trade work for everyone. That's not only moral, but it's rational too. It can help avoid an age of wasted potential and strife. The Great Depression was preceded by isolationism. Who wants to go through that again? Not me.
The point is, the ball is in the court of corporations and the wealthy. Money in politics will work for them until it doesn't. No amount of donations, ear whispering, and cocktail parties can avert popular rage. Trump supporters are only a taste of what may be coming, because Trump was easy on the rich (of course). There's no guarantee that the next populist president will be as nice to the rich. There's no guarantee that the next populist president won't be more capricious on free trade. The underlying ailments that gave rise to populism must be addressed as soon as possible. Critically, free trade is not the problem. The problem, like I said, is that the rich capture too much of the surplus from trade. More of that surplus should be going to education, bullet trains, research, socialized healthcare, etc...and it's not.