But while the legalization now being talked about fits into that pattern in a sense, the sheer scope of its overreach would put it in a different category as a practical matter. That overreach is not mitigated but exacerbated by the fact that the president apparently intends to be selective: We are told he may offer effective legal amnesty to about half of the 11 or so million people who are here illegally. Which half? And why not the other? The president apparently intends to answer these questions based on criteria of his choosing, with no clear foundation in any particular statutory authorization or provision of law.

President Obama has long treated Congress with contempt, and has on many occasions taken executive actions that have bent or broken the limits of the executive’s discretion in our system. Perhaps above all, he has enforced Obamacare selectively — ignoring some clear requirements of law and conjuring up others that do not exist. These have been serious violations of his obligation to see that the laws are faithfully executed, and have caused serious problems for our system of government. They will leave the next president with a lot of damage to undo. But what the administration appears to be contemplating here is of a different scale and character. It is not selective enforcement of a new statute but rather just an action outside the law, in an arena in which the president himself has said unilateral action is beyond his authority and in which there is no case for extreme urgency.