correction: An earlier version of this editorial listed an incorrect number of House Republicans who have signed a measure to put bills to protect “dreamers” up for a floor vote. It also misstated the number of additional Republicans necessary for the measure to pass. This version has been updated.

Members of the Border Network for Human Rights and Borders Dreamers and Youth Alliance protest outside a U.S. federal courthouse in El Paso to demand that Congress pass a clean Dream Act. (Jose Luis Gonzalez/Reuters)

DOZENS OF congressional Republicans have claimed to be concerned for “dreamers” who grew up and attended school in the United States, only to face the threat of deportation thanks to President Trump’s decision to rescind protections they were granted by an Obama-era program. Now they have a chance to prove they meant it.

A scattering of moderate Republicans in the House of Representatives — 18, at last count — have signed on to a measure that may force their GOP colleagues to do what they’ve been content to avoid: vote on a bill to protect dreamers from deportation. Just seven more Republicans would be needed to put bills to protect dreamers up for a floor vote, assuming all 193 House Democrats support the maneuver, known in Congressionalese as a “discharge petition.”

A floor vote sounds like a modest goal; a bill would still need Senate support and then a signature from Mr. Trump, whose erstwhile professions of “love” for dreamers have turned to dust. Measured against the inertia and paralysis on immigration enforced by Republican congressional leaders, however, a vote by the full House would count as a breakthrough. It could generate momentum for action, that rare commodity in Washington.

Predictably, House Speaker Paul D. Ryan (R-Wis.) is aghast at the possibility that a vote to protect dreamers, supported by large majorities of Americans, might be foisted on his Republican caucus in an election year. To Mr. Ryan, doing the right thing is secondary to ensuring that no legislation advance without a Republican majority. Nor is he likely to summon the political courage to challenge Mr. Trump, whose likely price for protecting dreamers has steadily risen, to include billions of dollars to build a border wall, plus draconian restrictions on legal immigration. “I want to have a vote on something that can make it into law,” said the speaker. “I don’t want to have a vote on show ponies.”

Yes, Mr. Ryan has always found a way to sidestep tough votes on immigration and dreamers, despite his professed backing for a bill to protect them. That’s what prompted the handful of Republicans, some of whom are retiring, to force his hand.

They did so with a parliamentary mechanism that would put four immigration bills before the full House, one of which would be at Mr. Ryan’s discretion. The others are: a straight path to citizenship for dreamers; a conservative bill that trades temporary legal status for dreamers for tougher enforcement measures and tighter limits on legal immigration; and a bipartisan proposal that includes both legalization for dreamers and some modest steps toward beefing up the border, but not a wall. Whichever bill receives the most votes above a majority would be passed along to the Senate.

The proposal presents a stark choice to Republican moderates such as Rep. Barbara Comstock, who represents a suburban Virginia district that Hillary Clinton won easily in 2016 — and where thousands of dreamers live. Stay silent, and assent to the potential victimization of hundreds of thousands of blameless young immigrants, Americans in all but the strictest legal sense, who hold such promise. Or muster the political backbone to force Congress to do its job — and vote.