Time and again, I think you see that the issue of immigrant- and immigration-bashing just doesn't carry the political force that its advocates are constantly claiming and that all-too-many of its opponents seem to fear. I recall when it started to seem like maybe Mike Huckabee could be a serious contender and he, notwithstanding a sensible record on immigration, decided to go hire hard-core restrictionist Jim Pinkerton. Just before going to work for Huckabee, Pinkerton was going around Washington talking about how despite Iraq and the economy, immigration was going to deliver the election to the GOP. It turned out that restrictionism couldn't even win a Republican primary.
I don’t think there’s any question that many immigration restrictionists overstate the salience of the issue. (That’s what single-issue activists do!) But one reason that “restrictionism couldn’t even win a Republican primary” is that every single candidate – including John McCain, in rhetoric if not reality – ran as, well, a “secure the borders first” restrictionist. Now, some of them were more plausible in this role than others, but if you were a GOP voter following the race casually rather than obsessively, I think you’d be forgiven for assuming that all of the candidates were more or less on the same page on the issue. It’s not as if John McCain swept to an easy victory while promising to immediately revive comprehensive immigration reform; he limped and stumbled to a plurality victory while promising that he’d learned the error of his ways on the issue. This suggests that immigration may not matter to GOP primary voters as much as Jim Pinkerton thinks it does, but not that it doesn’t matter at all.
Likewise, I tend to think that immigration restrictionism could carry a great deal of “political force” in a general election – but only if it were handed with finesse and moderation, rather than the sort of “Death of the West” hysteria that seems like the default mode for too many immigration opponents. Americans want border security and they want a lower immigration rate; what they don’t want is to feel like they're being asked to vote for “Operation Wetback, Part II.” Unfortunately, it doesn’t seem like there are any Republican politicians who actually believe in the moderate-restrictionist position. Instead, there are politicians who make restrictionist promises they don't intend to keep in the hopes of keeping the yahoo vote appeased, and politicians who sound like, well, yahoos themselves. Campaigning on a moderate-restrictionist position hasn’t been tried and found wanting; it’s been left more or less untried.