The Supreme Court's decision announced Monday in the Arizona v. United States case opens the way for sensible reform of our immigration laws.
Barack Obama and his administration have taken heart that the court overturned Arizona's state penalties for illegal immigrants. The idea is that states can't pile higher penalties on top of those voted by Congress, just as states can't deport people who Congress allowed into the country.
But the much more significant part of the case was the unanimous 8-0 (Justice Kagan not voting) ruling upholding the Arizona provision authorizing state and local law enforcement personnel to help enforce federal law by asking those stopped for other reasons to show that they are citizens or legal immigrants.
This has been derided as a "where are your papers?" provision redolent of an authoritarian regime. But federal law has long required legal immigrants to carry their papers. And just about every adult carries a driver's license or equivalent without feeling oppressed.
What seems out of date now is the attitude, common in some liberal circles, that it's unsporting if not oppressive to enforce the law against illegal immigrants. Cities like San Francisco have declared themselves "sanctuary cities" with no obligation to enforce federal laws they don't like.
The underlying theory seems to be that it's unjust to bar anyone from entering our country. But that's obviously nonsense. Under international law, we have no obligation to admit anyone to the United States except accredited diplomats. We open our borders to visitors and legal immigrants not because we have to but because we think it's in our interest to do so.
Now we seem to be moving for a variety of reasons to a situation where we can control our borders and discourage illegal immigration far better than we have been doing for the last three decades.
One reason is the Arizona law that the court upheld, as well as similar laws in other states. Even more important is improved technology and our willingness to use it.
Arizona has required employers to use the recently improved eVerify system to match job applicants and Social Security numbers, and Census data suggests this has reduced the state's illegal population significantly. Large corporations are using eVerify, if only to protect themselves from bad publicity and expensive lawsuits. There's a move to require its use nationally.
Certainly it's not beyond our technological capacity to keep track of non-citizens. Visa and MasterCard manage to monitor a very large number of people with minimal error rates. India -- India! -- has issued unique identity cards to its 1.2 billion residents.
Back when our immigration laws were last revised, in 1986, both left and right hated the idea of national identity cards. But now we have such cards in all but name and don't seem to mind being tracked by our banks or by Google or Facebook.
For years, we were told that effective enforcement was impossible. Now it's becoming technically very feasible.
And for years we were told that the tide of illegal immigrants would continue inexorably for years and decades to come. But now the illegal population is dropping because of reverse migration back to Mexico. And, in my view anyway, it's unlikely to increase to previous levels again.
Barack Obama continues to address the issue as if the facts had not changed. When he speaks to Hispanic groups, he calls for immigration legislation with mass legalization provisions, though he did nothing to advance it when his party had supermajorities.
And he's attracted attention by announcing his administration won't deport young illegals who meet certain conditions -- in line with the "Dream Act" bill he couldn't get Congress to pass.
In contrast, Mitt Romney in his speech to a Latino group limited his offer of citizenship to those who serve in the military. He was criticized for not setting out significant legalization provisions.
But Romney did address what is now the central problem with our immigration policy. And that is that current law is tilted against high-skill entrants who want to come here. We're shutting the door on math and science Ph.D.s even as Canada and Australia are welcoming them in.
The upholding of the Arizona law helps reduce the number of illegals, even as we debate which of them should be allowed to stay. But the key issue now is how we facilitate high-skill immigration.