Democratic candidate Bernie Sanders, who opposed the Trans-Pacific Partnership trade deal, called it “a continuation of other disastrous trade agreements such as NAFTA, CAFTA and normal, long-term trade relations with China.” He believes that free trade agreements have led to the loss of American jobs and lower U.S. wages. Sanders said America needs to rebuild its production base with U.S. factories for well-paying jobs for the U.S. workforce, instead of relocating to China and elsewhere.    The adoption of NAFTA has led to the removal or removal of barriers to trade and investment between the United States, Canada and Mexico. The impact of the agreement on issues such as employment, the environment and economic growth has been the subject of political controversy. Most economic analyses have shown that NAFTA has been beneficial to North American economies and the average citizen, but has been detrimental to a small minority of workers in sectors subject to trade competition.   Economists have estimated that the withdrawal from NAFTA or the renegotiation of NAFTA, in a way that would have created restored trade barriers, would have affected the U.S. economy and cost jobs.    However, Mexico would have been much more affected, both in the short term and in the long term, by the loss of jobs and the reduction of economic growth.  According to the Sierra Club, NAFTA has contributed to the increased use of fossil fuels, pesticides and GMOs.  NAFTA has also contributed to environmentally harmful mining practices in Mexico.
 It has prevented Canada from effectively regulating its oil sands industry and has created new legal opportunities for transnational companies to combat environmental legislation.  In some cases, environmental policy has been neglected as a result of trade liberalization; In other cases, NAFTA`s investment protection measures, such as Chapter 11, and measures to address non-tariff barriers to trade have threatened to discourage stronger environmental policy.  The most severe increases in pollution attributable to NAFTA were in the base metals, Mexican petroleum and transportation equipment sectors in the United States and Mexico, but not in Canada.  The North American Free Trade Agreement (NAFTA), which came into force in 1994 and created a free trade area for Mexico, Canada and the United States, is the most important feature of bilateral trade relations between the United States and Mexico. On January 1, 2008, all tariffs and quotas were eliminated for the United States.