Derb, I don’t think it’s either/or. Nor do I think it’s just a government phenomenon, though that’s a big part of it.
The fact is that we are culturally proud of our immigrant heritage. As a nation, we want to encourage immigration. We of course want it to be the legal kind, but you would have to pay for that. This would require many more border patrol and immigration agents than we have ever provided for, and a bigger and more efficient bureaucracy for processing immigration applications.
Law enforcement, no less a creature of human nature than any of us, always performs better when it is accountable. If the laws are being applied to everyone, it is much easier to face down the strawberry farmers. On the other hand, when there are not enough resources to manage immigration, it is a given that you are tolerating law-breaking, and therefore you are much more likely to buckle — after all, why give the strawberry farmers a hard time if you’re not giving much of one to anyone else.
The other cultural issue here is the outsized fear of Big Brother, which comes up in many national security contexts. I’ve never understood how it is that people willingly endure very intrusive physical searches at airports and blithely abide the fact that credit companies and all manner of private marketers warehouse their personal information, sell it, data-mine it, etc, but yet, when Uncle Sam says it would help security if it had some — not nearly all, but just some — similar information in a database, all hell breaks loose. The civil libertarians and the privacy extremists go crazy and gloom us all about how the Constitution is being shredded. That, I think, is the reason you can’t swipe your social security card the way you do your bank and credit cards. I, too, believe it’s nutty, but it’s more of a culture problem than an enforcement problem.