As Donald Trump moves from the midterm to his reelection campaign, he has a bit of a problem, although it’s one that’s familiar to “populists” who actually win office. Can he keep his supporters fired up with fury at the way things are going in America after he’s been in charge of it for four years?

This isn’t just an abstract issue. As Paul Waldman notes, it’s coming up right now in a notably less-enthusiastic installment of that hardy right-wing perennial, the War on Christmas:

“[S]ince it’s the holiday season, the War on Christmas must be fought yet again, our annual Brigadoon of resentment and outrage-mongering. But the truth is that with a Republican in the White House, fighting the culture war becomes awkward and, at times, even more ridiculous than usual….

“In fact, you can see the discomfort on the faces of Fox News hosts when they trot out the old scripts about how Christmas is being beaten down by the powerful forces of secularism …

“That highlights a problem facing the culture warrior: Even if what you’re fighting against are broad social forces and demographic changes that play out over decades, when your party is in charge in Washington it becomes harder to convince people that we’re in a living hell where all of our values have been discarded and our people are horribly oppressed.”

More specifically, when you are as prone to chest-thumping self-aggrandizement as the 45th president — who treats perilous trade wars as great victories, each peaceful moment on the planet as a foreign policy triumph, and every positive economic indicator as a benchmark of human progress — when exactly do your complaints about the Powers That Be lose credibility? This problem is reflected in the difference between Trump’s 2016 and 2020 campaign slogans: “Make America Great Again” and “Keep America Great.” At some point during Trump’s beneficent rule, greatness must have bloomed across our land.

It’s true that Trump can always find objects of wrath that, while not as powerful as himself, still threaten his great regime: the news media, of course; liberal judges; the academic proctors of political correctness; the elitists of Hollywood; and various fools and knaves in both political parties who don’t get it. In some respects, it is useful for him that Democrats now control one-half of one-third of the federal government; it makes it slightly less embarrassing to whine about the mulishness of Congress when your own party doesn’t control it entirely.

But still, Trump will not be able to entirely evade the fact that he is now not an outsider, but the unquestionable symbol of the status quo in Washington. And he’s not the sort of person who can discipline himself to pose as the brave and lonely insurgent. Not when there are military parades to plan and photo ops with powerful world leaders to stage.

Obviously, if conditions in the country turn Elysian by 2020, this will be less of a problem for the incumbent president. And if terrible things happen — well, that could give Trump fresh opportunities to stand for change, or at least a stark choice of policy options for dealing with crises. But if things rock along steadily with good and bad news, and Trump getting his way some of the time but not all the time, then the thematics will get very tricky.

It’s tough to be a megalomaniac in the most powerful job in the world who has to admit he does not have magical powers to solve all problems. At some point his followers may begin to doubt his magic, too, particularly if he proclaims America great again when life for its citizens doesn’t seem so hot.