THE QUESTION IS, WHO WILL STOP HIM? Megan McArdle: Mr. President, You Can’t Do Whatever You Want.

On Sunday, Ross Douthat of the New York Times wrote an uncharacteristically blistering attack on the plan being floated by the Barack Obama administration to quasi-legalize the status of almost half the immigrants who are now in the country illegally. The details remain somewhat vague, but according to the Washington Post, “Ideas under consideration could include temporary relief for law-abiding undocumented immigrants who are closely related to U.S. citizens or those who have lived in the country a certain number of years — a population that advocates say could reach as high as 5 million.”

This is not the first time that the administration has floated this trial balloon, so I think it’s safe to say that it is contemplating sweeping unilateral executive action that would grant millions of undocumented immigrants protection from deportation and issue work permits that would allow them to earn a legal living while they are here — at least, unless the news media or the public pushes back.

I quite agree with Ross: The media and the public should push back. I say this as someone who is broadly supportive of greater legal immigration, and who has tangled with immigration opponents in the past. Whatever your opinion on immigration policy, I hope it doesn’t involve supporting giving the president extremely broad powers to simply rewrite any law that he thinks ought to be different. To see why, you need only ask yourself a simple question: Would you like to give this power to a president from the opposing party on a law where the two of you disagree?

I’m sure Ted Cruz already has a list drawn up. Plus:

The defenses that have so far been mounted of this proto-plan are so far completely underwhelming. There is, for example, the argument that we have to expect this, because Congress is so dysfunctional that the president can’t get any laws passed. But this is a terrible example of congressional dysfunction; immigration bills have been failing in Congress for years now, not because Congress is gridlocked, but because this is a difficult and contentious issue, and there’s not really a ton of political support for increased immigration. Furthermore, polls on this issue seem to be moving in the wrong direction for the president. In this environment, the most functional Congress in the world might well politely decline to pass a bill that does what the president is proposing.

Indeed.