I'm always a bit amused (saddened, angered, whatever) by the willingness of the conservatarians to apply rigid cost-benefit analyses to legislation they don't like (Food Stamps, Environmental regs, etc...) while utterly ignoring such considerations for things they do like (the Iraq War). Regardless of the merits of the intent, it's just hard to see how spending $20 billion to militarize our southern border has been a particularly good deal.
The first time I hit an internal border check, about 50 miles North of the Mexican border, I was really really shocked. I didn't know our country did such things.