Speaker Mike Johnson had a ready-made refrain when asked why Republicans weren’t moving to extend federal health care subsidies: their party wanted to help 100% of Americans with their costs, not just the 7% of Americans enrolled in Affordable Care Act plans.

But not 100% of his conference agreed.

A rare revolt from the moderate wing of the party has upended Johnson’s plans. Four Republicans this week signed onto a Democratic discharge petition that guarantees that the House will vote on extending the ACA subsidies sometime in January, with Republican leaders now powerless to stop it.

For Democrats, it was vindication of a months-long strategy, starting with the government shutdown in the fall, that pushed the expiration of the ACA support to the forefront of politics. Republicans from competitive districts most at risk of losing their seats in next year’s midterms felt the political pressure as they heard from constituents about their skyrocketing premiums.

“Nothing has changed with House Republican leadership, but something has changed within their own ranks,” said Rep. Pete Aguilar, chair of the House Democratic Caucus.