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).  President Trump has made the renegotiation of NAFTA a central platform for his presidential campaign. On February 2, 2017, shortly after taking office, President Trump announced his intention to begin negotiations with Canada and Mexico to revise NAFTA, and on November 30, the leaders of the three countries signed the agreement. The revised final agreement was then signed by their respective trade agents on December 10 of this year. Both President Trump and congressional Democrats, who have pushed for further reflection on labor reform resulting from the original agreement, declare the agreement a victory, while Canadian and Mexican states also announce more favourable provisions for their countries. On June 19, 2019, the Mexican Senate ratified the agreement (114 yes, 3 no, 3 abstentions).
 Mexico`s ratification process will be completed when the President announces its ratification to the Federal Register. „The USMCA is a great victory for American agriculture and I am pleased that the Canadian Parliament has approved the agreement today,“ said U.S. Agriculture Minister Sonny Perdue. „The USMCA locks in and expands access to our northern and southern neighbours. I thank President Trump for negotiating this agreement and for always supporting American farmers and ranchers. We will continue to work with Canada and Mexico to implement this agreement. 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.  A new addition to the USMCA is the inclusion of Chapter 33, which covers macroeconomic policies and exchange rate issues.
This is considered important because it could set a precedent for future trade agreements.  Chapter 33 sets out requirements for currency and macroeconomic transparency that, in the event of a breach, would be grounds for litigation under Chapter 20.  The United States, Canada and Mexico currently meet all of these transparency requirements in addition to substantive policy requirements that comply with the international Monetary Fund`s articles.  The new agreement increases the requirement for more spare parts in North America to avoid tariffs.