Aliens flock to this country because they need the work. At the same time, America is overloading its prisons with more criminals than the system can handle. A partial solution could be realized by outsourcing contract prisons in Mexico. This would alleviate some of each problem.
It would be cheaper than incarcerating prisoners in this country and could also employ thousands of Mexicans. Perhaps the incentive to go to jail would be reduced as well. Naturally, the U.S. standards for prisons would have to be met.