THE FAILURE of immigration reform to make headway in the Republican-dominated House of Representatives is a chronicle of a death foretold. House Republican hard-liners, including tea partiers, have spent years broadcasting their intransigence. That White House officials and moderate Republicans continued plugging away in hopes of a compromise was an exercise mostly in wishful thinking. That is now over.

What comes next is less clear. Informed by Speaker John A. Boehner (R-Ohio) that the House would take up no immigration bill this year, President Obama last week vowed to move without Congress, using his executive powers.

But the fact that Congress has chosen inaction, no matter how irresponsibly, does not grant plenipotentiary powers to the executive; Mr. Obama cannot rule by fiat. If, as White House aides have suggested, Mr. Obama elects to grant more mass reprieves from deportation, he does so at the risk that Congress and the courts may reverse his moves.

True, the original sin in the immigration debate rests with Republicans in Congress, who have blocked any reasonable reform. House GOP members have refused to take up a sweeping overhaul of the immigration system passed more than a year ago by the Senate. In its place they have offered no alternative to address the problem of 11 million illegal immigrants, most of whom have been in this country for at least a decade.

Congress’s failure has left in place a state of dysfunction ripe for crisis. The latest is a surge in illegal border crossings in the Rio Grande Valley by tens of thousands of unauthorized immigrants, many of them unaccompanied children. In the last nine months, more than 50,000 such minors have been apprehended along the southwestern border, more than twice the number from the same period last year.

Many come under the belief, in some cases justified, that they will be allowed to stay for months or years as they await a hearing in immigration court on their claims for protection or asylum. That has overwhelmed already burdened detention centers.

This is unsustainable. The United States cannot tolerate a free-for-all on the border that encourages vulnerable Central American children to risk their lives traversing Mexico. Immigration advocates warn of a humanitarian disaster if thousands of children are turned back. They should not minimize the humanitarian disaster caused by encouraging children to subject themselves to smugglers and harsh conditions in the false belief that America, once reached, will welcome them permanently.

Mindful of that, Mr. Obama is seeking more than $2 billion from Congress to reinforce the border and accelerate the processing of these minors. Rightly, the administration is also seeking to modify existing law by streamlining deportation procedures to discourage young, unauthorized immigrants from making a dash for the border.

Sadly, a tougher stance on deporting youngsters caught along the border may be the only modification to existing immigration law that Republicans in Congress will accept. In the absence of a comprehensive solution, this country will continue to fend off crises and plug holes without addressing the millions of undocumented immigrants who have been in America for years. That may reassure Republican incumbents who fear primary challenges from anti-immigration fire-breathers. It does nothing to fix a broken system.