I've had some nice discussion of immigration with some readers through comments. Gary Gross at Let Freedom Ring has posted a couple of complimentary posts, which are of course very nice. But I like the tug of good debate, and Nathan Bissonette of St. Paul, who has joined the upper echelons of MOB readership and commentship (?) has been giving good comments on the viability of fences. We had a debate in comments here and then went to email to hash some things out. The question is whether there are comparable fences we can look at to see whether fences are efficacious. (I know, I know, "It's obvious that ..." There's something in that sentence opener that raises my antennae. Call me pedantic if you wish.) Thus I argued against using the Israeli security barrier as a comparable to the fence that would be erected by the Senate or House bills. Here's the end of the exchange between us, which I think states well the point I'm trying to make about these bills (Nathan in italics):

But the San Diego fence doesn't share the Israeli fence's problems. It's designed to keep out Mexicans. It's enforced American style - no shooting. It's worked to cut border crossing in San Diego because illegals simply walk around the end of the fence. So it works where it's built. So why not extend the fence all the way to Texas?

Why isn't the experience of the San Diego fence instructive as to the effectiveness of an Arizona fence?

I have two issues. First, I am unsure how much effect it had on national statistics. How many people went around the fence and how many were sufficiently discouraged not to try at all? I don't think the numbers in the LAT piece said anything about that, just the SD immigrant flow? How would we know? I'm sure it had some effect, but we're looking quantitatively for its marginal effect. And we don't know that yet.

Second, we can't easily extrapolate from a 13 mile fence to a 1300 mile fence. Are there economies of scale or diseconomies? Again, it's not to say it absolutely will not work. I don't know that. Neither do its supporters. I'm just cautioning people not to oversell the fence and to be sure they understand the need for employer sanctions as a necessary bulwark for the fence. THAT was why we needed the House bill to get to conference, to get those sanctions put in. I still think some way to get illegals into the system by offering to use monetary punishments rather than incarceration for violations of immigration laws only (any other law they break, they pay the full price including potentially jail) will bring more out of the shadows and allow for better enforcement, but just like in the case of the fence we don't know that yet. I think it would, but if a bill came out of conference that had real employer sanctions and either length of fence and nothing else, it would be much, much better than either house's bill in itself.

I agree with Gary's report of Matthew Dowd's commentary, and say let's chill out and make the two bills come together into something that deals with employers who hire illegals. I haven't any idea if the biometric card proposed works or not; that's an engineering problem that others will solve. But there has to be priority given to solving it somehow, now, or else this thing goes the same way as Simpson-Mazzoli did, which also had plenty of support. It just didn't have enforcement.