There are three primary dispute settlement mechanisms that are included in NAFTA. Chapter 20 is the resolution mechanism from one country to another. It is often considered the least controversial of the three mechanisms and was maintained in the USMCA in its original NAFTA form. Such cases would involve complaints between USMCA member states for violation of a provision of the agreement.  Chapter 19 deals with the justification of anti-dumping or countervailing duties. Without Chapter 19, the remedy for the management of these policies would be through the national legal system. Chapter 19 provides that a USMCA body hears the case and acts as the international commercial court in mediating the dispute.  The Trump administration has attempted to remove Chapter 19 of the new USMCA text, although it has been maintained so far in the agreement. On June 19, 2019, the Senate of Mexico ratified the agreement (114 yes, 3 no, 3 abstentions).  Mexico`s ratification procedure will be completed when the President announces ratification in the Federal Register. During the 2016 presidential campaign, Donald Trump promised to renegotiate NAFTA, which he called “the worst trade deal ever.” As president, he did.
The result is the USMCA, which Trump signed in January and which he considered one of his most significant achievements in his State of the Union address. On April 3, 2020, Canada informed the United States and Mexico that it had completed its domestic ratification process for the agreement.  After the announced loss of 2500 auto worker jobs at the General Motors plant in Oshawa and many others at factories in the United States, Trump had already threatened to impose tariffs on cars from Mexico in retaliation against the company. Senator Elizabeth Warren has said she will not support the deal when it comes to a vote in the Senate. On March 1, 2019, many organizations representing the agricultural sector in the United States announced their support for the USMCA and asked Congress to ratify the agreement. They also called on the Trump administration to maintain NAFTA until the new trade agreement is ratified.  On March 4, however, House Ways and Means President Richard Neal predicted a “very hard” path through Congress for the deal.  Beginning March 7, senior White House officials met with members of the House Ways and Means as well as moderate caucuses from both sides, such as the Solvers Caucus, the Tuesday Group, and the Blue Dog Coalition, to gain support for ratification. The Trump administration has also withdrawn from the threat to withdraw from nafta, as negotiations with Congress continue.  Fox News reported on December 9, 2019 that negotiators from the three countries have reached an agreement on implementation, paving the way for a final agreement within 24 hours and ratification by all three parties before the end of the year. Mexico has agreed to the imposition of a $16 per hour minimum wage for Mexican autoworkers by a “neutral” third party.
Mexico, which imports all of its aluminum, has also objected to the provisions on U.S. steel and aluminum content in automotive components.  An April 2019 International Trade Commission analysis of the likely effects of the USMCA estimated that the agreement, if fully implemented (six years after ratification), would increase U.S. real GDP by 0.35% and increase the U.S. . . .