Jonah is right that, as a legal justification, racial and ethnic preferences are often justified by the need for “diversity” or some other bogus rationale besides historical discrimination. But the latter is, I am convinced, what really underlies whatever support such preferences still command. So it makes perfect sense for Congress to say: “Look, we really don’t like preferences, and indeed we have banned them. The courts, in their wisdom, have carved out an exception to our laws. We’re willing to let that some of that exception stand, for now, but since the real rationale for the exception is historical discrimination, we want to invalidate that exception in those cases where there can be no plausible justification for it—i.e., for people who have just arrived.”
As for policing this, the legislation contemplated would not set up an Office for Recent Immigrant Blood Detection or anything like that. But those agencies, employers, and universities that afford preferences would be required to make clear that recent immigrants have to disqualify themselves. Doubtless some who should disqualify themselves will not, just as there is no real effort to stop fraudulent claims of minority status now. But some immigrants, maybe even most, will disqualify themselves, and that would be good thing.
Speaking for myself, another major motive for proposing the legislation is to use the high visibility of the immigration debate to dramatize just how ridiculous the use of preferences is—for immigrants and nonimmigrants alike. If the Left insists that immigrants are as entitled to preferences as nonimmigrants, its unwillingness to draw this distinction should, as far as most people are concerned, simply hasten the demise of preferences across the board.