The U.S. Trade Representative (USTR) formally notified Congress on May 18, 2017, that the United States intended to renegotiate and modernize NAFTA with Canada and Mexico. Under U.S. trade law, this started a required consultation period before talks could begin. It marked the official launch of the process that later produced the USMCA.
Negotiators from the United States, Canada, and Mexico opened the first round of NAFTA renegotiations in Washington, D.C., beginning August 16, 2017. The talks aimed to update rules written in the early 1990s for a more digital and integrated economy. This began a multi-round negotiation cycle that would continue through 2018.
On August 27, 2018, the United States and Mexico announced an agreement in principle on key parts of a revised NAFTA. This step narrowed major issues—especially on autos and trade rules—and increased pressure to finalize a trilateral deal including Canada. It set up the final negotiating phase that produced the USMCA framework.
On September 30, 2018, the United States, Mexico, and Canada announced they had reached an agreement on a new pact: the United States–Mexico–Canada Agreement (USMCA). The announcement signaled that the NAFTA renegotiation had moved from debate over principles to a near-final text. It also started the process of domestic review and eventual ratification in each country.
On November 30, 2018, the leaders of the United States, Mexico, and Canada signed the USMCA at the G20 summit in Buenos Aires. Signing did not make the agreement law; each country still had to complete its own ratification steps. Still, the signature locked in a shared text and moved the process decisively into legislatures and implementing agencies.
Mexico published a sweeping labor reform decree on May 1, 2019, reshaping union rules and labor justice institutions. The reform was closely linked to USMCA labor commitments (including Annex 23-A) and became central to U.S. congressional debate about enforceability. This step helped address concerns that workers’ rights needed stronger protection for the new trade deal to move forward.
On June 19, 2019, Mexico’s Senate ratified the USMCA, making Mexico the first of the three countries to approve it. This ratification showed Mexico’s priority on maintaining stable North American trade rules. It also increased focus on what changes (if any) would be needed to secure approval in the United States and Canada.
On December 10, 2019, the three countries signed a Protocol of Amendment to revise the 2018 USMCA text. The changes reflected negotiations aimed at winning broader U.S. bipartisan support, especially around labor and environmental enforcement and certain intellectual property provisions. The amended package cleared a key political obstacle by aligning the agreement with conditions demanded for U.S. passage.
On December 12, 2019, Mexico’s Senate approved the USMCA amendments contained in the Protocol of Amendment. This mattered because changes negotiated to satisfy U.S. lawmakers still had to be accepted by the other parties. Mexico’s approval helped keep the revised agreement on track for final U.S. and Canadian votes.
On December 19, 2019, the U.S. House of Representatives passed the USMCA Implementation Act by a 385–41 vote. This vote was a major turning point because U.S. approval had been the largest remaining political hurdle after Mexico’s earlier ratification. The action moved the agreement to the U.S. Senate and signaled unusually broad bipartisan support for a large trade pact.
On January 16, 2020, the U.S. Senate approved the implementing legislation by an 89–10 vote. With passage in both chambers, the United States had completed its main legislative step needed to implement the agreement domestically. The vote cleared the way for the President’s signature and final coordination on entry-into-force timing with Canada and Mexico.
On January 29, 2020, the President signed the USMCA implementing legislation into law (Public Law 116-113). This converted congressional approval into U.S. domestic legal authority to apply the agreement’s new rules. With U.S. law in place, attention shifted to Canada’s ratification and the final procedural notifications required for the agreement to start.
On March 13, 2020, Canada’s implementing bill (Bill C-4) received Royal Assent, completing Canada’s domestic legislative approval. This was essential because the USMCA could not take effect until all three countries finished their internal procedures. Canada’s action helped set up the final step: formal notifications that triggered the agreement’s start date.
On April 24, 2020, USTR notified Congress that Canada and Mexico had taken measures necessary to comply with USMCA commitments and that the agreement would enter into force on July 1, 2020. This notification reflected the completion of required domestic procedures by all three parties. It provided certainty to businesses and agencies preparing to shift from NAFTA rules to USMCA rules.
On July 1, 2020, the USMCA entered into force, formally replacing NAFTA for trade among the United States, Mexico, and Canada. From that date, preferential tariff treatment and compliance shifted to USMCA rules (such as updated rules of origin and new labor and digital trade provisions). This marked the conclusion of the 2017–2020 negotiation-to-implementation arc and the start of the agreement’s operational phase.
USMCA Negotiation, Signing, and Ratification Process (2017–2020)