The idea that more trade is good (on balance) is deeply engrained in anybody who went to graduate school in economics. In May 1930, over a thousand economists had written a letter encouraging President Hoover to veto the Smoot-Hawley bill. And yet there is something else economists do know but tend to keep closely to themselves: the aggregate gains from trade, for a large economy like the United States, are actually quantitatively quite small. The truth is, if the US were to go back to complete autarky, not trading with anybody, it would be poorer. But not that much poorer.
