The impetus for a North American free trade zone began with U.S. president Ronald Reagan, who made the idea part of his 1980 presidential campaign. After the signing of the Canada–United States Free Trade Agreement in 1988, the administrations of U.S. president George H. W. Bush, Mexican President Carlos Salinas de Gortari, and Canadian prime minister Brian Mulroney agreed to negotiate what became NAFTA. Each submitted the agreement for ratification in their respective capitals in December 1992, but NAFTA faced significant opposition in both the United States and Canada. All three countries ratified NAFTA in 1993 after the addition of two side agreements, the North American Agreement on Labor Cooperation (NAALC) and the North American Agreement on Environmental Cooperation (NAAEC).