Securing U.S. congressional approval for NAFTA would have been impossible without addressing public concerns about NAFTA’s environmental impact. The Clinton administration negotiated a side agreement on the environment with Canada and Mexico, the North American Agreement on Environmental Cooperation (NAAEC), which led to the creation of the Commission for Environmental Cooperation (CEC) in 1994. To alleviate concerns that NAFTA, the first regional trade agreement between a developing country and two developed countries, would have negative environmental impacts, the CEC was given a mandate to conduct ongoing ex post environmental assessment of NAFTA.