President Obama’s executive order on immigration was the big topic on the weekend shows. And I don’t just mean the ones that run on Sunday morning.

“Saturday Night Live” opened with a spoof of the old “I’m Just a Bill” cartoon from Schoolhouse Rock. Just as Mr. Bill is explaining how he’s supposed to become a law, President Obama comes along, pushes him down the steps of Capitol Hill, and introduces his new friend—Mr. Executive Order. “You see son, there’s an even easier way to get things done around here.”

If you haven’t seen the video yet, it’s worth watching. It's clever and funny, although, to be fair, it doesn't get the policy details quite right.

The video suggests that Obama’s executive order gives legal status to as many as 5 million undocumented workers. It doesn’t. It merely gives them a temporary reprieve from deportation and the opportunity to get working papers—and, even then, only if they apply, pay a fee, and pass background checks. (Claire Groden has a rundown of the process at QED.) Obama’s successor could undo the order just as unilaterally, and as quickly, as Obama did. That is one reason that most lawyers, including many conservative lawyers, think the action is plainly constitutional.

But the harder question has always been about the unwritten rules of politics, not the written ones. By acting on his own, so soon after his party suffered a defeat in the midterm elections, has Obama violated previous understandings of what a president should and shouldn’t do? Will it create a precedent that future presidents can exploit, quite possibly for purposes that liberals will regret?