What Mexico does is relevant: they have a 100% no tolerance for illegal immigration, yet they scream to high heaven when we start to get the least tough with their people sneaking across our border. If for no other reason than to defy their double standard, we should have a 100% no tolerance policy on illegal immigrants from Mexico.
Some here want to oversimplify the situation and make it all a matter of emotion. It isn't just a propaganda issue for the right, it's a matter that should be of concern to all Americans: we are being invaded by people who not only are breaking the law, but who pay dearly for the dubious privilege of doing so. In the process they're fueling organized crime and thus contributing to violence not just here but across the continent. Going easy on people coming across the border is thus, on two fronts, a pro-crime policy.
Those who are already here are a different problem. They're still lawbreakers, but many have already woven themselves into the fabric of their communities. They must be penalized, but avenues have to be provided for them to remain part of the communities they've settled into. But again, that is oversimplifying; many have families, but many -- perhaps more -- are single. Those with families, especially with U.S. citizen children, have to be treated differently.
For my part, I liked the Bush concept of a $5k fine per illegal entrant, though I'd give them ten years to pay it off; meanwhile they'd be on supervision. But for single males, I'd be inclined to offer a choice between stripped of all their property toward payment of their fine, and being summarily dumped in some random place back in their own country, or joining the Army -- where they'd have required classes in English, American history, the Bill of Rights, and so on; if they passed those successfully, then after completing a four-year term of service they'd get their residence card. Oh -- and their fine would come out of their military pay.
I wouldn't make citizenship that easy. It's too easy for those of us born here, already; in general we don't appreciate it or take it seriously. Everyone and anyone who wants to vote, run for office, have a government job, or have a business getting government contracts, ought to have to complete two years of national service, whether military or something else. Those immigrating should have to complete four.