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 can not 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