Unilateral Trade Policy Disarmament

At Tech Central Station, Arnold Kling rails,

The idea that we need to "negotiate" reductions in trade barriers is absurd. Trade barriers primarily damage the country that erects the barriers.
He dreams the far-flung dream where rationality meets idealism, in other words, where commonsense bumps into political deadlock.
We do not need a U.S. trade representative. Our trade policy should be unilateral disarmament, because the weapons in the trade war are all suicide bombs.
Will somebody please grab ahold of congressional members' attention and say, "Look, what you're doing makes no economic sense. You need to stop because you don't understand the harm you're causing and the extent you're limiting gains. No really, stop it, you haven't the right to ruin other people's financial lives." Yet another pipedream: first that of implementing a economist's logic, then that of winning politicians to it despite every contrary political-economic force pushing away.