In late 2019, the Trump administration received support from Democrats in Congress for the USMCA, after agreeing to strengthen the implementation of the work. In the updated pact, the parties agreed on a number of changes: the rules of origin for the automotive industry have been strengthened, so that 75% of each vehicle must come from the Member States, compared to 62.5%; and new work rules have been added, which require 40 percent of each vehicle from factories that pay at least $16 an hour. A proposal to extend intellectual property protection for U.S. pharmaceuticals – a red line for U.S. negotiators – has been sacrificed. The USMCA is also upgrading the controversial investor-state dispute settlement mechanism, eliminating it completely with Canada and limiting it to certain sectors with Mexico, including oil and gas and telecommunications. 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.  Canada ratified the agreement in March and the USMCA came into force on July 1, 2020.
Although NAFTA is officially dead, governments and businesses are still adapting to the new rules, especially the new labour rules. Coronavirus can also complicate implementation as manufacturers adapt to new guidelines in the midst of a global economic crisis. On May 11, 2018, House Of Representatives spokesman Paul Ryan set May 17 as the deadline for congressional action. This deadline was not met and the agreement with Mexico was not reached until August 27, 2018.  At that time, Canada had not approved the agreement. Mexico`s outgoing President Enrique Pea Nieto, having left office on 1 December 2018 and requiring 60 days as a review period, the deadline for making the agreed text available was set at the end of September 2018, 30 September 2018. Negotiators worked around the clock and reached an agreement less than an hour before midnight on a draft text. The next day, October 1, 2018, the USMCA text was published as an agreed document.
The agreement is the result of a renegotiation between the member states of the North American Free Trade Agreement, which gave informal agreement on 30 September 2018 and officially on 1 October under the new agreement.  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.