The impetus for NAFTA actually began with President Ronald Reagan, who campaigned on a North American common market. In 1984, Congress passed the Trade and Tariff Act. This is important because it gave the President "fast-track" authority to negotiate free trade agreements, while only allowing Congress the ability to approve or disapprove, not change negotiating points. Canadian Prime Minister Mulroney agreed with Reagan to begin negotiations for the Canada-U.S. Free Trade Agreement, which was signed in 1988, went into effect in 1989 and is now suspended since it's no longer neeeded. (Source: NaFina, NAFTA Timeline)