Jonah Goldberg is no fan of a national ID card, but he explains for National Review Online readers today why a society with a liberal welfare state is bound to seek ways to identify its citizens, or make them “legible.”

[T]he Prussians, under Otto von Bismarck, had famously created the first modern administrative state, which included the precursor to America’s Social Security system and what today might be called “jobs programs.” The Prussians also pioneered the public-school system in order to make the people more legible to the state — imposing common language, political indoctrination, and the like.

A system of reliable ID was necessary for conscription and internal security — government’s top concerns — but it was also necessary to properly allocate the benefits and jobs the state doled out in order to buy popular support, and to enforce school attendance.

And this brings me to our current debate over Arizona’s immigration laws. Opponents like to conjure the police-state association of “Ihre papiere, bitte.” I think that’s wildly exaggerated (and so do several Supreme Court justices, apparently). But as someone who’s against a national ID card, I’m sympathetic to the concern nonetheless. The Constitution lists three federal crimes — treason, piracy, and counterfeiting — but today we have more than 4,500 federal crimes, all because the government in Washington wants to make the American people more legible. I don’t want to make that easier with a national ID card.

But what I wish liberal opponents would understand is that in a society where the government “gives” so much to its citizens, it’s inevitable that the state will pursue ways to more clearly demarcate the lines between the citizen and the non-citizen.

Most (but by no means all) conservatives I know would have few problems with large-scale immigration if we didn’t have a welfare state that bequeaths so many benefits on citizens and non-citizens alike. I myself am a huge fan of legal immigration. But if you try to see things like a state for a second, it’s simply unsustainable to have a libertarian immigration policy and a liberal welfare state. Ultimately, if you don’t want cops asking for your papers, you need to get rid of one or the other.