Although President Donald Trump warned Canada on September 1 that he would exclude them from a new trade deal if Canada did not comply with its demands, it is not clear that the Trump administration has the power to do so without congressional approval. :34-6 According to reports by the Congressional Research Service (CRS), one was published in 2017 and another on July 26, 2018, it is likely that President Trump would need congressional approval for fundamental changes to NAFTA before the changes are implemented. : 34-6 A 2015 study showed that Mexico`s prosperity increased by 1.31% due to NAFTA tariff reductions and 118% for Mexico`s intra-blocking trade.  Inequality and poverty have decreased in the regions of Mexico most affected by globalization.  Studies from 2013 and 2015 showed that Mexican small farmers benefited more from NAFTA than large farmers.   According to the Sierra Club, NAFTA has contributed to significant export-oriented agriculture, resulting in an increase in the 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.
 NAFTA was supplemented by two other regulations: the North American Agreement on Environmental Cooperation (NAAEC) and the North American Agreement on Labor Cooperation (NAALC). These tangential agreements should prevent companies from moving to other countries in order to use lower wages, more moderate health and safety rules and more flexible environmental rules. The U.S. Chamber of Commerce attributed to nafta that U.S. trade in goods and services with Canada and Mexico increased from $337 billion in 1993 to $1.2 trillion in 2011, while the AFL-CIO held the agreement responsible for sending 700,000 U.S. manufacturing jobs to Mexico at that time.  Fifth, all NAFTA countries were required to respect patents, trademarks and copyrights. At the same time, the agreement ensured that these intellectual property rights did not affect trade.