Immigrants and supporters hold a rally in support of the Deferred Action for Childhood Arrivals program. (Frederic J. Brown/Agence France-Presse via Getty Images)

PRESIDENT TRUMP found a facile way to deflect blame for his decision to terminate the program that provides safe harbor for the "dreamers," some 800,000 young immigrants brought illegally to this country as minors. Lacking any policy conviction — as a candidate, Mr. Trump vowed to end the program, then once in office said the "incredible" young dreamers should breathe easy — he ducked, dodged and shunted the issue to Congress.

Agreed: Congress should have dealt with the dreamers years ago, and several times tried to do so. It failed, which is why President Barack Obama established Deferred Action for Childhood Arrivals, which grants two-year renewable reprieves from deportation, along with work permits. Mr. Trump did not kill the program outright, which may have disappointed some of his hardcore supporters. But he handed it a slow-motion death sentence, unless Congress can break its long-standing deadlock on the issue.

The president didn't have the spine to announce his decision himself. He shuffled it to Attorney General Jeff Sessions, an anti-immigration extremist who seemed to relish sticking a knife in DACA. Mr. Trump told reporters Tuesday that he hoped "Congress will be able to help" the dreamers "and do it properly." But his written statement — "young Americans have dreams too" — was a study in ambiguity. While saying the dreamers wouldn't be first in line for deportation, Mr. Trump put them on a path to lose jobs, educational opportunities, and the ability to lead open and unafraid lives.

Tossing red meat to the administration's hardcore nativist base, Mr. Sessions falsely asserted that DACA amounts to unconstitutional "amnesty." In fact, DACA is a stopgap that conferred no legal status on its recipients. And despite the administration's contention that it is legally indefensible, predicting how the Supreme Court would rule on it is a guessing game. Presidents have long exercised broad discretion over the enforcement of immigration law and deportations — a matter of necessity given finite resources.

By calling attention to the plight of a sympathetic group of generally hard-working, law-abiding young people, DACA has clarified for many Americans just how senseless it would be to deport hundreds of thousands of them. That's one reason Congress should act to extend their protections.

Another is that the dreamers are a boon to the U.S. economy. They are English speakers; nearly all are in school, college or the workforce; and tens of thousands of them are working toward a bachelor's degree or higher. Most own cars and pay taxes. Many have bought houses and apartments; several thousand have even started businesses. Mr. Sessions is wrong to claim that the dreamers take jobs from Americans. In fact, the unemployment rate has plummeted in the five years since the dreamers have been eligible for work permits.

Mr. Trump's order is an assault on economic logic. By subverting the employment and educational prospects of so many promising young people, Mr. Trump has sapped their earnings and purchasing power, withdrawn their college prospects and imperiled their jobs. That's why more than 300 top executives of some of the largest U.S. corporations asked him not to rescind DACA. Now, unless Congress acts, the United States will suffer along with the dreamers.