Ideally, Mexico would help us police our shared border. But Mexico receives huge remittances from its citizens unlawfully working in the U.S., so it's currently in Mexico's interest to promote illegal immigration. A well-designed guest worker program, however, could change this and turn Mexico into a U.S. immigration ally.
President Bush has proposed creating a guest worker program in which many Mexicans would have the legal right to work temporarily in the U.S. Unfortunately, even with Bush's program in place Mexico would still encourage its people to work illegally in the U.S. and send home some of their pay.
So instead we should create a guest worker program under which the number of legal Mexican guest workers is based on the number of illegal Mexican immigrants in the U.S. For example, for every additional illegal Mexican immigrant who enters the U.S., the number of Mexican guest worker slots could be reduced by two. Under this plan, Mexico has an incentive to reduce illegal immigration into our country.
If you want Mexico's help on the border, find a way to tax Mexico for violations of the border. Miller acknowledges the challenges to implementation. It necessarily includes legitimizing what is now done illegally, and yet it may also involve penalties that are stiffer than what the pro-illegal-immigration crowd would be willing to accept. But it's an interesting idea to consider.