As the first month of the new year begins, it’s unclear how well President Donald Trump grasps the altered political reality he faces. Indeed, using the words “reality” and “Trump” in the same sentence is a non sequitur.

Incoming Democratic Speaker Nancy Pelosi’s plan to pass a clean budget resolution ending the government shutdown dramatizes how the president has put himself into a no-win position. Although the new budget proposal is all but identical to one passed unanimously by the Senate before Trump’s hostage-taking over his absurd “wall,” Senate Majority Leader Mitch McConnell says he won’t allow a vote on anything the president opposes.

That’s because it would almost certainly pass, which would clarify things considerably. So who owns the shutdown? Trump, who publicly declared on national TV that he’d be “proud” to shut down the government and promised not to blame Democrats — a characteristically worthless vow.

So what proportion of the American public supports Trump’s position? According to a recent Reuters/Ipsos poll reported by NBC News, “just 35 percent of those surveyed … said they backed including money for the wall in a congressional spending bill. Only 25 percent said they supported Trump shutting down the government over the matter.”

Even a substantial proportion of the president’s vaunted “base” recognizes The Wall as a dead-bang loser. The only remaining question is the exact form the White House’s eventual climb-down will take. Like The Washington Post’s estimable Jennifer Rubin, I’m betting on a modest increase in spending for border security with no mention of The Wall. Trump can then erect “steel slats” in a photogenic position and claim victory.

Meanwhile, House Democrats would be well advised to convene reality-based hearings on border security and immigration reform.

Trump’s wall would also be a potential disaster for threatened wildlife in the Big Bend region of Texas and elsewhere. Not to mention that much of the land required is privately owned and would need to be taken by eminent domain, a time-consuming and costly process. Those are merely some of the reasons why just about the only constituencies in the border region that appear enthusiastic about The Wall are “snowbirds” who relocated to places that actually used to be part of Mexico and are horrified to hear Spanish spoken.

Republican Rep. Will Hurd, whose southwest Texas district includes 820 miles along the Mexican frontier, has characterized Trump’s wall as “the most expensive and least effective way to do border security.”

As for restraining the drug trade, get real. There are probably more tunnels beneath the already-existing wall dividing Tijuana and San Diego than under the Hudson River between New York and New Jersey. Some have electric lights and small-gauge rail tracks. Bulk drug shipments arrive not on the backs of campesinos trudging through the Sonoran desert, but tourists carrying concealed packages, hidden compartments in 18-wheelers, cargo containers on ships and airplanes, and fishing boats retrieving contraband at sea.

Properly run congressional hearings might allay Trump-inspired fears about a nonexistent crisis at the border. “You know what the real problem is? It’s that there is a big lie going on,” author and commentator Linda Chavez said on CNN’s “State of the Union.”  “We are not in the middle of an immigration crisis in the United States. In the year 2000, 1.6 million people were apprehended trying to get into the United States. In fiscal year 2017, it was about 300,000. Now, it did tick up in 2018, and there has been a shift. We are no longer seeing single men coming to work in the United States. We’re seeing families who are fleeing violence in their countries. We do need to do something about the asylum system.”

Chavez, a Republican veteran of several administrations, grew up in New Mexico, and like millions of Americans, has relatives on both sides of the border.

Something else congressional hearings could clarify is that nobody’s for the “open borders” Trump rants about. Fear-mongering aside, most Americans do favor practical, humane reform of America’s broken immigration system.

Columnist Gene Lyons is a National Magazine Award winner and co-author of “The Hunting of the President” (St. Martin’s Press, 2000).