On January 16, 2020, the US Senate approved legislation implement the US-Mexico-Canada Agreement (USMCA) by a vote of 89 to 10, sending the legislation to President Trump to be signed into law. The Senate's approval follows a similarly lopsided vote in the House of Representatives, which approved the bill on December 19 by a vote of 385 to 41 (the widest margin in favor of any recent US trade agreement considered in the House). These votes occurred just weeks after the bill's introduction and publication, and despite the signing on December 10 of a "Protocol of Amendment" in which the Parties agreed on multiple, substantive changes to the USMCA text that had not previously been made public. Thus, despite Congress's approval of the USMCA, questions remain about the recent changes to the Agreement and how these and other novel USMCA provisions are reflected in the United States' implementing legislation. This report therefore examines the substance of the recent changes to the USMCA and the measures the United States intends to take in order to implement the Agreement. The report is organized as follows:

- Section I describes the key changes that the Parties agreed to in the Protocol of Amendment to the USMCA, signed in Mexico City on December 10;

- Section II provides an overview of the US implementing legislation, as well as the accompanying "Statement of Administrative Action" detailing actions the administration will take to implement the USMCA; and

- Section III discusses the likely next steps towards the USMCA's entry into force and the implications of the revised Agreement....