Don't you love it when I give a list of the matters I'll comment on someday and never comment on any of them?
But... immigration is certainly the hot-button domestic issue of the day (who exactly has put it there? I guess this is one issue on which the Republicans feel they have some sort of traction...).
I've heard plenty of ridiculous statements on both sides... but honestly, it's probably time to sit down and look at some hard facts:
(1) Illegal immigrants are going to keep coming, as long as there are employers for them.
(2) Illegal immigrants are less likely to use social services, because they're afraid of getting caught. I'm not going to go look up the numbers, but feel free to do so yourself. Additionally, in states such as the one I live in, there's no income tax, which means that immigrants do pay tax (sales tax). Those who are on the payrolls of legit corporations are accounted for in payroll taxes.
(3) The issue isn't that nobody would do the job immigrants do; American citizens/legal residents would do so. The question is what the expense would be. Raising the minimum wage might actually push more jobs into the informal category.
(4) The border is really, really long, and it would cost a lot of money, and burn a lot of (figurative) bridges, to build a barrier, not to mention probably be at least partially ineffective. Greater enforcement is also going to be pretty expensive.
(5) Guest worker = eventual permanent resident, whether you like it or not, and regardless of the technical law.
(6) Americans don't really want to pay higher prices for things.
So basically, point (5) suggests that a legitimate guest-worker program is pretty much impossible. You're left with three options: (a) Try to contain immigration and harshly penalize anyone employing immigrants, and greatly ramp up enforcement, (b) Say you're trying to achieve plan (a) [this plan is what's been going on for a long time], (c) Admit defeat, lift quotas on immigrants from the Americas and try to deal with it by bringing their jobs into the formal economy.
Plan (a) is extremely expensive, which is why so many administrations have been able to make do with plan (b). But now the issue is becoming intensely politicized, so plan (b) is no longer okay (at least for now). I would be tempted to say that the issue might slide out of the public view again, but now immigrants' rights groups also are mobilized on behalf of the human rights (health care, etc.) of illegal immigrants and the question is whether they will let it die.
What about plan (c)? Well, there would probably be more immigrants, at least at first. But, if you made the one requirement to cross having legal employment, and you made all the employers pay minimum wage, this would certainly raise costs for consumers, but not by as much as by converting the jobs to Americans who would likely demand higher wages. Moreover, you could do away with much border enforcement and cut costs there. It's a lot like the "war on drugs"... what exactly are we fighting, and what is our goal?