It's clear that President Trump is going to shake up U.S. trade policy, but what exactly he will do, and when, remains unclear.

Comments on the campaign trail and from the early days of the administration indicate that the nation might soon be pursuing an "America First" policy. Economic theory and experience offer little reason to believe that a move toward increased protectionism would benefit the United States.

The challenge for leaders with protectionist tendencies is that the benefits of global trade are spread across a wide constituency within the United States, including most consumers and educated workers, while the losses are very concentrated in terms of geography, industry, and socio-demographics.