"The North American Free Trade Agreement (NAFTA) entered into force on January 1, 1994. […] The overall economic impact of NAFTA is difficult to measure since trade and investment trends are influenced by numerous other economic variables, such as economic growth, inflation, and currency fluctuations. The agreement likely accelerated and also locked in trade liberalization that was already taking place in Mexico, but many of these changes may have taken place without an agreement. Nevertheless, NAFTA is significant, because it was the most comprehensive free trade agreement (FTA) negotiated at the time and contained several groundbreaking provisions. […] The 115th Congress faces numerous issues related to NAFTA and international trade. President Donald J. Trump has proposed renegotiating NAFTA, or possibly withdrawing from it. Congress may wish to consider the ramifications of renegotiating or withdrawing from NAFTA and how it may affect the U.S. economy and foreign relations with Mexico and Canada. It may also wish to examine the congressional role in a possible renegotiation, as well as the negotiating positions of Canada and Mexico. Mexico has stated that, if NAFTA is reopened, it may seek to broaden negotiations to include security, counter-narcotics, and transmigration issues. Mexico has also indicated that it may choose to withdraw from the agreement if the negotiations are not favorable to the country. Congress may also wish to address issues related to the U.S. withdrawal from the proposed Trans-Pacific Partnership (TPP) free trade agreement among the United States, Canada, Mexico, and 9 other countries."
CRS Report for Congress, R42965
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html