The left wing of the Democratic Party flourished this summer as fed-up liberals in key races across the country have eschewed traditional, more moderate candidates in favor of hard-charging progressives.

But behind the scenes, ultra-progressive House members and candidates are pushing their own party leaders to reflect more of that mood — arguing that Democratic leader Hakeem Jeffries and his allies are, so far, failing to grasp the demands of far-left voters who showed up in droves this summer.

Those liberals watched in alarm in recent weeks as Jeffries publicly disavowed their marquee “Medicare for All” bill while a pro-Israel Democrat was elevated to a key foreign policy role within the caucus. They also argue his allies were working to undermine a pair of progressive candidates in Michigan and California.

“I was very confused and surprised by that,” Rep. Pramila Jayapal, a senior progressive and author of the House’s “Medicare for All” bill, told CNN about the leader’s comments about her signature bill. She added that she has been having “direct” conversations with Jeffries about it.

The emerging frustrations on the left offer a preview of some of the pressures that await Jeffries if the party can flip the chamber next year, particularly as a new crop of far-left progressive candidates threaten not to support him for leader post-election.