Ronald Reagan was the first U.S. president to propose a trilateral free trade agreement between the nations of North America. His successor, George H.W. Bush, opened negotiations with Mexican President Carlos Salinas de Gortari, which Canadian Prime Minister Brian Mulroney later joined. The goal was to do away with most tariffs and barriers to the movement of people and products across the three countries’ borders. The debate over ratification of the treaty was heated in all three countries, with critics warning that it would have adverse affects on the ability of workers to organize and, as a result, depress wages. There were also environmental concerns, which were addressed by a side deal. All three nations ratified NAFTA in the end, and President Bill Clinton signed it into law on December 8, 1993. it took effect on New Year’s Day 1994.