Passport? To travel to Mexico.........Since when?
As of June 2009, US citizens entering the United States by land or sea must present a passport or other WHTI compliant travel document such as a passport card. The passport requirement is waived in some cases for minors. Read about travel documents for kids.
Check the link for details. NM driver's licenses don't count as a passport card, BTW as they are available to illegal aliens upon presentation of a utility bill or rent receipt!