You guys are missing the point. I'm not arguing the Constitution, I'm arguing the logic. You know that easy access to guns doesn't cause crime, even though guns are used in crimes. Criminals flout gun laws; if they can get guns legally they will, but if they can't get them legally, they'll find another way. But why then do you accept the logic that the easy access to our territory results in more terrorism? Yes, terrorists can get in legally, but if they couldn't, they'd find another way in.
There certainly are good reasons for overhauling immigration policy, nobody's denying that. My point is that counterterrorism is not among those reasons, any more than crime fighting is a reason for gun control.
Besides the fact that it is needlessly inflammatory, I still don't think your gun control analogy is a good one. Try this...
We passed a three strikes law in California which took a lot of criminals off the street. Did it stop all crime? No. Did it reduce crime? Yes. When a crime is committed now, are more resources available to solve that crime? Yes.
We're talking about needles and haystacks... Smaller stacks makes it easier to find the needles.
Fewer Illegals won't solve the problem of potential terrorists, but it makes it more solvable