From the Document: "Congress plays a major role in U.S. trade policy through constitutional authority over tariffs and foreign commerce (Article 1, §8). Since World War II, U.S. trade policy has generally sought to:  liberalize markets by reducing trade and investment barriers through agreements and negotiations;  foster an open and nondiscriminatory rules-based trading system, including through the World Trade Organization (WTO);  enforce trade commitments and laws;  support economic growth; and  offer relief to U.S. firms and workers from import competition and 'unfair' foreign trade practices. The Trump Administration's trade policy actions continue to present legislative and oversight issues for the 116th Congress, including on: significant unilateral tariff actions, a renegotiated North American Free Trade Agreement (NAFTA), and economic engagement and confrontation with China and other trading partners."
CRS In Focus, IF10156
Congressional Research Service: https://crsreports.congress.gov/