1) E-verify: This is the single most important thing we can do to combat illegal immigration because it gets to the root of why most illegals are coming here and staying here: jobs. If we mandate E-Verify -- which is really just a way to check the validity of Social Security numbers -- and the government puts the resources into the program, it will lock illegal aliens out of the overwhelming majority of jobs in America. Once we get to that point, there's no reason for most illegals to come here or for most of the illegals that are already here to stay here. So, if the flow of illegals into the country dramatically slows and the illegals that are already here begin to self-deport because they have no work, the biggest part of the problem is solved.
2) Finish the fence: The standard line from the open borders and amnesty crowd about the fence is, "If you build a thirty foot fence, somebody will just grab a forty foot ladder." However, we have built the fence out in a few places on our border and what we've found is that it actually works extremely well.
You've got to understand the purpose of the fence. It's not the end-all and be-all in border security; it's just a force multiplier. Illegals avoid areas where there's a fence and you don't need as much manpower there. That enables you to concentrate your manpower in other areas where it's impractical to build a fence (and there are some of those, such as where the border is a river and you'd be cutting off American livestock from their water supply).
We've already passed a law to build a fence on the border and it was supposed to be done in 2009. All we have to do is get the government to stop deliberately dragging its feet and finish the job.
3) More resources: The agencies that enforce our immigration laws may be the only thing in the entire federal government that's being deliberately underfunded. We don't have enough border patrol agents, we don't have enough agents enforcing the law internally, we don't have enough resources to detain the illegals we catch, we don't put the money that's needed in E-Verify, and for that matter, we don't even have enough resources to adequately handle legal immigration. Again, this is all by design. Heads, we win / Tails, you lose. You can pass any law you want, but if the government won't fund the people needed to enforce it and it won't put the resources needed to make sure that if we capture someone, we can hold onto him until he’s deported, then the law isn't going to be effective.
4) An effective visa program: One of the dirty legal secrets of illegal immigration is that as many as half of the illegals didn't sneak over the border. Instead, they came here legally with a visa and just didn't leave.
That's actually pretty easy for people to do since, believe it or not, the United States doesn't have an effective system for telling whether visa holders leave the country. If you come here on a visa and choose not to leave when it expires, chances are that the government has no idea you're still here. Technically, I-94 forms are supposed to be presented when visa holders leave the country, but there's minimal enforcement, people from 36 countries are exempt, and very little money and manpower are put into tracking down people who overstay their visas – like, for example, 4 of the 9/11 hijackers.
Unless we insist on having these forms filled out and start making a real attempt to track down more than a tiny fraction of the people who overstay their visas, we're not going to fix our illegal immigration problem.
5) Anyone caught doesn't ever come back legally: We've set up a system where there's no permanent penalty for being an illegal. If you try to cross the border and get caught, we send you back. If you do manage to make it across, you probably won't get caught. However, if you do, we may just let you go. Even if you do get deported, well, no big deal. You just try to creep back in and the cycle starts all over again. In theory, the penalties for "illegal re-entry" into the U.S. are harsh, but in practice they're often non-existent. Just ask Obama's Auntie Zeituni who was instructed to leave the country, didn't do it, got caught again and was allowed to stay here, in public housing, on the dole.
Here's an alternate idea. If you get caught in the United States illegally, we fingerprint you, take a DNA sample, and you are NEVER allowed to become a citizen or enter the United States legally again. That means if you have relatives here, you will NEVER be able to legally visit them. If we ever do create a guest worker program that you could potentially participate in, you'll be locked out. If you ever hope to be an American citizen, that will be off the table.
Some illegals won't care at all about this penalty, but for many illegals, this would be a tremendous disincentive to enter or stay in the United States illegally. You want to see illegals "self-deport?" This one change would drive millions of them out of the country.