The impacts of trade differ among groups, sectors, and regions. The demand and supply sides of trade policy in American politics have long interacted with each other, as the winners and losers of trade policy have called for new politics of trade. Will Trump`s America give up free trade policy and turn to protectionism? What are the policy demands from the American voters in the 2016 elections and how would politicians respond? This article explores the sources and processes of American trade policy from the perspectives of history, institutions, and elections. Indeed, protectionism would hurt the white working-class in the short term, because they are the consumers who used to buy those cheap imported goods through free trade. The Trump administration would take the initiative to renegotiate with or withdraw from the NAFTA countries. American voters` decisions between political motivations and economic calculations should be critical for the success or failure of the Trump presidency over the next two years.