The comments on my post indicate strong feelings and powerful disagreement, mirroring the strong feelings and powerful disagreement in Congress and in the nation as a whole. It should, however, be possible for Congress to work out a compromise along the following lines:
1. By a combination of sticks and carrots, it should be possible to induce the vast majority of illegal immigrants in this country either to step forward, admit their illegal status, regularize it, and thus enter the path to eventual citizenship (without having to leave the country), or depart for good. The only objections to this course that I can see are "unfairness" to would-be immigrants waiting patiently in the immigration queue--and I do not think the interests of foreigners should weigh heavily in U.S. public policy--and the injustice of "rewarding" illegality (the "amnesty" issue). But illegal immigration is not so serious a crime as to demand obeisance to Kant's claim that even if a society were about to dissolve, justice would require that it execute any condemned criminals. I take a more relaxed, pragmatic view of the dictates of legal justice.
2. By a combination of mandatory biometric ID for all people in the United States (a measure that would have independent value in crime control and terrorism prevention) and heavy penalties on employers of illegal immigrants, future illegal immigration could be largely halted without need to build an expensive Berlin Wall between the United States and Mexico.
3. Reform of immigration law and reorganization of the various agencies in the Department of Homeland Security that administer the law would shorten the queue for legal immigrants (and thus alleviate the "fairness" objection to "amnesty"), adjust the supply of immigrants to the demand of American employers, and switch preferential teratment from foreigners who have family connections in the Unied States to foreigners who have valuable skills.