Hi sandb,
at the present time, driver's licenses won't be a substitute for a passport. However, there's a movement afoot to make driver's licenses more secure, so that the passport requirement might change. From
this article in the
Arizona Republic.
Cost of the new card would be about $50. Once federal standards are developed for it, officials said, border states such as Arizona may be able to incorporate the card's features into driver's licenses, eliminating the need for residents to carry both.
This is an important issue in border states. We have good relations with Mexico and we'd like to be able to have efficient exchanges across the border. For example, I was just in Douglas, AZ, a few weeks ago and I'd estimate that 3/4 of the cars in the parking lot for Wallmart had Sonora, MX license plates. Can you imagine how much revinue will be lost if 3/4 of their customers can no longer shop there?
Overall, security at the border is a situation that needs to be fixed. However, requiring passports for day-trippers might not be optimal.
That's just my BZ$0.02, of course.
Dan