Central American migrants walk along the metal fence on the border between Mexico and Calexico, Calif., on Nov. 19. (Pedro Pardo/AFP/Getty Images)

WITH THE midterm elections behind him, President Trump has dropped his dark warnings of an “invasion” of undocumented migrant caravans, even as thousands of those migrants arrive at the border. For the president, the migrants, many of them desperate women and children fleeing violence in Honduras, were a convenient electoral foil. And the nearly 6,000 U.S. troops he sent to “guard” the border against the caravans were props in his political theater.

Mr. Trump has moved on, but the thousands of soldiers deployed at his command to repel the phony invasion will now spend Thanksgiving at the border without their families.

It is a remarkable misuse of the U.S. military, at a cost that may reach a couple hundred million dollars. Past presidents have sent troops to the border, but usually National Guardsmen, often to grapple with a more authentic problem and rarely in the numbers Mr. Trump cavalierly deployed. Most of the soldiers sent to the border in recent weeks aren’t anywhere near Tijuana, Mexico, near San Diego, where most of the migrants have arrived. Now comes word from the Army general commanding the border mission that some troops, having run out of tasks where they are, may be sent elsewhere — or home.

Notwithstanding Mr. Trump’s incendiary rhetoric, the problem of migrants is real. Many cross the border with their children and apply for asylum, overwhelming existing legal mechanisms, feeding what the president calls a “catch and release” revolving door for migrants freed as they await hearings, and contributing to a backlog of about 1 million cases in immigration courts.

A rational response would be to add to the 350 or so immigration judges, who cannot handle the tens of thousands of asylum claims flooding the immigration courts annually. The administration this year hired a few dozen judges, a fraction of what is required. As the caseload has more than quadrupled since 2006, the number of judges has not even doubled, according to congressional testimony in April by Judge A. Ashley Tabaddor, president of the National Association of Immigration Judges.

Despite that, Mr. Trump has sneered at the idea of hiring more, even after aides pressed him to do so. “Who are these people?” he raged, before suggesting darkly that adding many new judges would somehow corrupt the system. “Now can you imagine the graft that must take place?” he asked.

Granted, new hiring can be challenging, in vetting and cost. But any major challenge involves scaling up resources and personnel, and it’s hard to see why that’s beyond the government’s capabilities.

On the other hand, maybe Mr. Trump prefers having an issue rather than a solution. He has made it clear he believes the immigration question propelled him into the White House. Now, by ramping up his inflammatory rhetoric, and by over-the-top measures such as sending thousands of troops to the border, it seems apparent Mr. Trump has opted for crisis instead of constructive improvements to what he rightly calls a broken system. If he actually wanted to solve the problem, he would send the troops home and hire hundreds of judges.