Immigration activists in the rotunda of the Russell Senate Office Building on Feb. 7 in Washington. (John Moore/Getty Images)

PRESIDENT TRUMP has often spoken and tweeted of the soft spot in his “great heart” for “dreamers,” the hundreds of thousands of young immigrants brought to this country as children. This supposed concern has now been revealed as a con.

Offered bipartisan legislation in the Senate that would have protected 1.8 million dreamers from deportation, in return for a down payment on the $25 billion wall Mr. Trump assured voters that Mexico would finance, the president showed his cards. The deal was a “total catastrophe,” the president said, punctuating a day in which the White House mustered all its political firepower in an effort to bury the last best chance to protect an absolutely blameless cohort of young people, raised and educated as Americans.

Despite the withering scorn heaped on the bipartisan plan by Mr. Trump, with a hearty second by Senate Majority Leader Mitch McConnell (R-Ky.), eight Republican senators backed it, giving it a total of 54 votes — six shy of the 60 required for passage. Had Mr. Trump stayed silent, or suggested he could accept a modified version, the bill may very well have passed. But he turns out to be far less interested helping the dreamers — helping anyone, really — than in maintaining his anti-immigrant political base.

His own blueprint, an obvious nonstarter that included sharp cuts to legal immigration, mustered just 39 votes in the Senate, nearly all Republicans. That’s a telling total, one that mirrors the percentage of Americans who still support him. Of the four immigration measures voted on in the Senate last week, the Trump bill had the least support.

The White House wasn’t surprised. By yoking its proposal for protecting dreamers to a hard-line wish list, the president guaranteed its defeat — and maintained the president’s own bona fides as a resolute champion of the nation’s xenophobes.

The president, along with Mr. McConnell, is intent on a blame game, not a solution. He suggested no compromises and engaged in no negotiations, preferring to stick with maximalist demands. Despite barely mentioning it as a candidate, Mr. Trump has not budged from insisting on a plan to reduce annual legal immigrants to the United States by hundreds of thousands, to the lowest level in decades.

That’s bad policy for a country with an aging population and an unemployment rate that ranks among the lowest in the industrialized world. More to the point, even if you favor lower levels, it was guaranteed in the context of this debate to doom the dreamers — especially after Democrats had already compromised substantially on the border security that Mr. Trump initially set as his price.

And what of the dreamers, whom Mr. Trump addressed repeatedly in calming tones, telling them not to worry? For the time being, federal courts have preserved their work permits and protections from deportation. Meanwhile, though, his administration is pressing ahead, asking the Supreme Court to uphold the president’s effort to end Deferred Action for Childhood Arrivals, the Obama-era program that has shielded dreamers since 2012.

If the administration is successful, as many legal experts expect, the lives, hopes and futures of nearly 2 million young immigrants will be upended. They will lose jobs and, in many cases, driver’s licenses, tuition subsidies and health insurance. They will slip into the shadows in the only country they know. This will be Mr. Trump’s legacy and the true reflection of his “great heart.”