Originally Posted by Greg B

Because it would make too much sense to do so. In this case, Schwartzenegger went head to head with the administration and got what he wanted.

The only reason the administrations from present to past didn't give a shit about the borders is because it would have impeded the transportation of drugs, money, prostitutes. It's a cash cow and what is best for the people of the U.S. and Mexico isn't what the government is concerned with. Their only concern is the maintaining of the criminal activities of the ruling class.