The agreed text of the agreement was signed by the heads of state and government of the three countries on November 30, 2018, as an incidental event at the 2018 G20 summit in Buenos Aires, Argentina.  The English, Spanish and French versions will also be binding and the agreement will take effect after ratification by the three states through the adoption of enabling laws.  This agreement is the result of a renegotiation between the member states of the North American Free Trade Agreement between 2017 and 2018, which formally approved the terms of the new agreement on 30 September 2018 and 1 October.  The USMCA was proposed by U.S. President Donald Trump and signed on November 30, 2018 by Trump, Mexican President Enrique Pea Nieto and Canadian Prime Minister Justin Trudeau as a secondary event of the 2018 G20 summit in Buenos Aires. A revised version was signed on December 10, 2019 and ratified by the three countries, with final ratification (Canada) taking place on March 13, 2020 just before the Canadian Parliament adjourned due to the COVID-19 pandemic. The U.S.-Mexico-Mexico Agreement (USMCA) is a trade agreement between these parties. The USMCA replaced the North American Free Trade Agreement (NAFTA). National procedures for ratifying the agreement in the United States are governed by the legislation of the Trade Promotion Authority, which is also known as the fast-track authority.
The negotiations focused “primarily on car exports, tariffs on steel and aluminum, as well as the milk, egg and poultry markets.” A provision “prevents any party from enacting laws that restrict the cross-border flow of data.”  Compared to NAFTA, the USMCA increases environmental and labour standards and encourages domestic production of cars and trucks.  The agreement also provides up-to-date intellectual property protection, gives the U.S. more access to the Canadian milk market, imposes a quota for Canadian and Mexican auto production, and increases the customs limit for Canadians who purchase U.S. products online from $20 to $150.  The full list of differences between USMCA and ALEFTA is listed on the Website of the United States Trade Representative (USTR).  Growing objections within Member States to U.S. trade policy and various aspects of the USMCA have had an impact on the signing and ratification process. Mexico said it would not sign the USMCA if tariffs on steel and aluminum were maintained. Based on the results of the November 6, 2018 U.S. election, it has been speculated that the greater power of Democrats in the House of Representatives could jeopardize the passage of the USMCA agreement.   Bill Pascrell, a senior Democrat, argued for changes to the USMCA to pass Congress.  Republicans have opposed the USMCA provisions that impose labour rights on LGBTQ and pregnant workers.  Forty Republicans in Congress have asked Mr. Trump not to sign an agreement that includes “the unprecedented integration of sexual orientation and the language of gender identity.” As a result, Trump ultimately signed a revised version that required each nation only to “policies it deems appropriate to protect workers from discrimination in the workplace” and said the United States would not be required to introduce additional non-discrimination laws.  The Canadian government expressed concern about the changes that have occurred under the USMCA agreement.  On November 30, 2018, the USMCA was signed as planned by the three parties at the G20 summit in Buenos Aires.   Disputes over labour rights, steel and aluminum prevented ratification of this version of the agreement.   Canadian Deputy Prime Minister Chrystia Freeland, U.S. Trade Representative Robert Lightizer, and Mexican Under-Secretary of State for North America Jesus Seade officially signed a revised agreement on December 10, 2019, ratified by the three countries on March 13, 2020.