The 116th Congress faces policy issues related to the Trump Administration's renegotiation of the North American Free Trade Agreement (NAFTA) and the proposed United States-Mexico-Canada Agreement (USMCA). On May 18, 2017, the Trump Administration sent a 90-day notification to Congress of its intent to begin talks with Canada and Mexico to renegotiate and modernize NAFTA, as required by the 2015 Trade Promotion Authority (TPA). Talks officially began on August 16, 2017. Negotiations were concluded on September 30, 2018. The proposed USMCA was signed on November 30, 2018. The agreement must be approved by Congress and ratified by the governments of Mexico and Canada before it can enter into force. The first NAFTA negotiations were launched in 1992 under President George H.W. Bush and continued under President William J. Clinton, who signed the implementing legislation on December 8, 1991 (P.L. 103-182). NAFTA entered into force on January 1, 1994. It is particularly significant because it was the most comprehensive free trade agreement (FTA) negotiated at the time, contained several groundbreaking provisions, and was the first of a new generation of U.S. FTAs later negotiated. Congress played a major role during its consideration and, after contentious and comprehensive debate, ultimately approved legislation to implement the agreement. NAFTA established trade liberalization commitments and set new rules and disciplines for future FTAs on issues important to the United States, including intellectual property rights protection, services trade, dispute settlement procedures, investment, labor, and environment. NAFTA's market-opening provisions gradually eliminated nearly all tariff and most nontariff barriers on merchandise trade. The proposed USMCA, comprising 34 chapters and 12 side letters, retains most of NAFTA's market opening measures and most of its chapters, while making notable changes to auto rules of origin, dispute settlement provisions, government procurement, investment, and intellectual property rights (IPR) protection. It also modernizes provisions in services, labor, and the environment. New trade issues, such as digital trade, state-owned enterprises, anticorruption, and currency misalignment, are also addressed. Key issues for Congress in regard to the proposed USMCA include the constitutional authority of Congress over international trade, its role in revising, approving, or withdrawing from the agreement, U.S. negotiating objectives and the extent to which the proposed agreement makes progress in meeting them as required under TPA. Congress may also consider the agreement's impact on U.S. industries, the U.S. economy, and broader U.S. trade relations with Canada and Mexico. The timing for congressional consideration of the proposed USMCA is unclear in part because of the TPA timeline and also because of issues of interest and concern voiced by Congress, including the level of enforceable labor provisions, auto rules of origin, and investor-state dispute settlement. Some policymakers have stated that the path forward to passage of the USMCA by Congress is uncertain partially because the three countries have yet to resolve disputes over U.S. steel and aluminum tariffs imposed by the Trump Administration. The United States, Canada, and Mexico are currently in a trade dispute over U.S. actions under Section 232 of the Trade Act of 1962 to impose tariffs on such imports due to national security concerns. In response to the U.S. action, Mexico and Canada initiated World Trade Organization dispute settlement proceedings and retaliated against certain U.S. exports. The conclusion of the proposed USMCA did not resolve the Section 232 tariff dispute. The United States, Canada and Mexico are currently in a trade dispute over U.S. actions under Section 232 of the Trade Act of 1962 to impose tariffs on such imports due to national security concerns.