Please review your concepts. NAFTA was signed in 1992, it came into effect in 1994. It couldn't have been signed in 1994 since it came into effect right on the 1 January 1994. Obviously it cannot come into effect before it was signed, unless it was mysteriously signed at 00:00 on 1 January 1994, which wasn't the case. If you have any doubts, please review the following articles ,  (this one by the US gov't), and finally from the NAFTA's webpage itself . Please stop changing the date. NAFTA was signed in 1992, not in 1994.