On May 30, U.S. Trade Representative Robert E. Lighthizer presented Congress with a draft declaration on the administrative steps needed to implement the U.S.-Mexico Agreement (USMCA and the new NAFTA), in accordance with the 2015 Presidential Trade Promotion (TPA) Administrative Action Statement. The project will allow congress to be presented to Congress, after 30 days, on June 29, a law to implement the USMCA. In a letter  to Nancy Pelosi, House of Representatives spokeswoman Kevin McCarthy, the minority leader of the House of Representatives, the Republican, told Lighthizer that the USMCA was the gold standard in U.S. trade policy, modernizing the competitive trade in digital, intellectual property and services in the United States and creating a level playing field for U.S. businesses. , workers and farmers, an agreement that represents a fundamental shift in trade relations between Mexico and Mexico. The USMCA is expected to have a very small impact on the economy.
 An International Monetary Fund (IMF) discussion paper published at the end of March 2019 stated that the agreement would have a “negligible” impact on the general economy.   The IMF study predicted that the USMCA “would have a negative impact on trade in the automotive, textile and clothing sectors, while achieving modest welfare gains, mainly due to improved access to the goods market, with a negligible impact on real GDP.”  The IMF study found that the economic benefits of the USMCA would be greatly enhanced if Trump`s trade war ended (i.e., when the United States lowered tariffs on steel and aluminum imports from Canada and Mexico and Canada and Mexico lowering retaliatory duties on imports from the United States)  In an appendix to the agreement , Mexico has also committed to enact large-scale laws to combat forced labour and violence against workers and to allow independent unions and labour tribunals. The International Trade Commission estimates that if the changes are made, they will increase the wages of unionized workers in Mexico and reduce their wage differences with American workers. In addition, there is a provision that the agreement itself must be reviewed every six years by the three nations, with a 16-year forfeiture clause. The contract may be renewed for a period of 16 years during the six-year review period.  The introduction of the Sunset clause gives more control in the organization of the future of the USMCA in the hands of national governments. However, there is concern that this could lead to greater uncertainty. Sectors such as automotive require significant investment in cross-border supply chains.  Given the dominant position of the U.S. consumer market, it is likely that this will put pressure on companies to establish more production in the United States, with a higher probability of higher production costs for these vehicles.  On May 11, 2018, House Of Representatives critic 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. In the chapter “Health and Plant Health Measures” (SPS), the United States, Mexico and Canada agreed to strengthen disciplines for scientifically sound SPS measures, while ensuring that the parties respect their sovereign right to the protection of life, animals, animals and plants or health.