Feb 01, 2008 — People coming over the border from Canada or Mexico now have to provide proof of citizenship. Yesterday, border agents started requiring a passport or military identification card. A state-issued I-D, like a driver's license, will only be accepted with a birth certificate. An oral declaration of citizenship won't be enough to get back across the border. U.S. officials have promised a grace period, and said agents will hand out informational fliers. Martha Foley has more.