They say failure can be a good teacher, but, so far, the Obama administration is opting out of the course. The post-midterm period has been one of the most bizarre of the Obama presidency. President Obama has racked up some impressive foreign-policy accomplishments, but, domestically and politically, things are off the rails.

Usually presidents use midterm defeats as a chance to rethink and refocus. That’s what Obama did four years ago. Voters like to feel the president is listening to them.

But Obama’s done no public rethinking. In his post-election news conference, the president tried to reframe the defeat by saying the turnout was low, as if it was the Republicans’ fault that the Democrats could only mobilize their core base. Throughout that conference, the president seemed to detach himself from his own party, as if the Democrats who lost their jobs because of him were a bunch of far-off victims of some ethereal malaise.

Usually presidents at the end of their terms get less partisan, not more. But with his implied veto threat of the Keystone XL oil pipeline, President Obama seems intent on showing that Democrats, too, can put partisanship above science. Keystone XL has been studied to the point of exhaustion, and the evidence overwhelmingly suggests that it’s a modest-but-good idea. The latest State Department study found that it would not significantly worsen the environment. The oil’s going to come out anyway, and it’s greener to transport it by pipeline than by train. The economic impact isn’t huge, but at least there’d be a $5.3 billion infrastructure project.

Usually presidents with a new Congressional majority try to figure out if there is anything that the two branches can do together. The governing Republicans have a strong incentive to pass legislation. The obvious thing is to start out with the easiest things, if only to show that Washington can function on some elemental level.

But the White House has not privately engaged with Congress on the legislative areas where there could be agreement. Instead, the president has been superaggressive on the one topic sure to blow everything up: the executive order to rewrite the nation’s immigration laws.

The president was in no rush to issue this order through 2014, when it might have been politically risky. He questioned whether had the constitutional authority to do this through most of his first term, when he said that an executive order of this sort would probably be illegal.

But now the president is in a rush and is convinced he has authority. I sympathize with what Obama is trying to do substantively, but the process of how it’s being done is ruinous.

Republicans would rightly take it as a calculated insult and yet more political ineptitude. Everybody would go into warfare mode. We’ll get two more years of dysfunction that will further arouse public disgust and antigovernment fervor (making a Republican presidency more likely).

This move would also make it much less likely that we’ll have immigration reform anytime soon. White House officials are often misinformed on what Republicans are privately discussing, so they don’t understand that many in the Republican Party are trying to find a way to get immigration reform out of the way. This executive order would destroy their efforts.

The move would further destabilize the legitimacy of government. Redefining the legal status of five million or six million human beings is a big deal. This is the sort of change we have a legislative process for. To do something this seismic with the stroke of one man’s pen is dangerous.

Instead of a nation of laws, we could slowly devolve into a nation of diktats, with each president relying on and revoking different measures on the basis of unilateral power . creating unstable swings from one presidency to the next. If President Obama enacts this order on the transparently flimsy basis of “prosecutorial discretion,” he’s inviting future presidents to use similarly flimsy criteria. Talk about defining constitutional deviancy down.

I’m not sure why the Obama administration has been behaving so strangely since the midterms. Maybe various people in the White House are angry in defeat and want to show that they can be as obstructionist as anyone. Maybe, in moments of stress, they are only really sensitive to criticism from the left flank. Maybe it’s Gruberism: the belief that everybody else is slightly dumber and less well-motivated than oneself and, therefore, politics is more about manipulation than conversation.

Whatever it is, it’s been a long journey from the Iowa caucuses in early 2008 to the pre-emptive obstruction of today. I wonder if, post-presidency, Mr. Obama will look back and regret that he got sucked into the very emotional maelstrom he set out to destroy.