Washington — Everybody seems to know what President Trump wants except President Trump.

He was foolish enough to believe he wanted a deal that would allow 700,000 undocumented immigrants brought here as children to stay. An arrogant 32-year-old White House aide, Stephen Miller, had to set the president straight: No, Trump learned, apparently he does not seek a fair and compassionate agreement on the Deferred Action for Childhood Arrivals (DACA) program after all.

Trump thought he wanted a “big, beautiful wall” along the southern border, with Mexico paying the cost. Chief of staff John Kelly had to explain to members of Congress that Trump never really meant a wall per se, but rather something more like a sketchy, intermittent fence. In a tweet attempting to reign in Kelly, Trump nonetheless asked U.S. taxpayers to ante up $20 billion to build it.

The president still believes he wants Senate Majority Leader Mitch McConnell to invoke the “nuclear option” and change the rules to allow legislation to pass with just 51 votes. Aides and allies have tried mightily to point out that McConnell doesn’t have 51 GOP votes he can rely on — which means that going nuclear would only force Republicans to stop blaming their own dysfunction on the Democrats.

Trump, bless his cold little cinder of a heart, remains under the impression that he calls the shots on administration policy. Is he so engrossed in what he obviously views as his most urgent task — watching hours and hours of cable news — that he doesn’t see how he has become marginalized? Is he so dense that he doesn’t realize he’s not being served by friends and supporters, but rather being used?

Those are rhetorical questions. Trump has always wanted to preside, not actually lead; and whenever he strays into the weeds of policy, he gets hopelessly lost.

It must have been humiliating for the president to make a DACA deal with Senate Minority Leader Chuck Schumer and then be countermanded by a callow subordinate. Trump has repeatedly pledged to extend legal status for the “Dreamers” affected by DACA, at one point calling them “these incredible kids.” But now his aides won’t let him fulfill that promise.

Whatever Trump thinks his views on DACA might be at a given moment, actual administration policy is being guided by Miller, Kelly and Attorney General Jeff Sessions, with help from lawmakers such as Sen. Tom Cotton, R-Ark. — hard-liners who want tough new restrictions on legal as well as illegal immigration.

There is no reason to question or minimize Trump’s fundamental bigotry — he opened his presidential campaign by calling Mexican immigrants “rapists” and this month ranted against newcomers from “s---hole countries” in Africa. But everything is personal with him, and he seems to waver when he thinks of the actual individuals involved. He appears to seek a solution that allows him to continue to use the immigration issue for purposes of demagoguery, but that does not ruin the life of, say, a young woman who was brought here illegally as an infant and went on to graduate from college with honors.

Words and elections have consequences, however. Trump’s rhetoric implies a race-based, religion-based immigration policy that prioritizes white Christians over people of color and Muslims. Whenever Trump wanders from that path, the hard-liners are quick to guide him back on course.

The deal struck by the Senate Monday to end the brief weekend-long government shutdown did nothing, really, to resolve the DACA issue. The government remains open until Feb. 8 — yes, the richest, most powerful nation in the world is functioning on a week-to-week basis. McConnell agreed that if there is no DACA deal by that date, he will allow a free and open debate on immigration.

The stage is thus set for a repeat performance: Facing a deadline when the government must be funded or shutter its doors, Congress will struggle to find a way to let the dreamers stay — a position held by 87 percent of Americans, according to a recent CBS News poll — while also shifting immigration policy toward “merit,” which has become code for “white people and maybe a few Asians, instead of black people and brown people.”

The irony is that coalitions of Democrats and moderate Republicans in both chambers would probably pass stand-alone legislation giving legal status to the Dreamers, if McConnell and House Speaker Paul Ryan would allow such a vote.

Would Trump sign that bill into law? Nobody really knows — least of all the president himself. He’ll have to wait for Miller, Kelly, Sessions and Cotton to give him his marching orders.

Eugene Robinson