The House of Representatives is set to return from its summer recess next week to vote on the Democrats’ $3.5 trillion budget resolution — which the Senate passed earlier this month along party lines. But it’s unclear if House leadership will have the votes to pass the budget blueprint, as a group of nine moderate Democrats threaten to withhold their votes.

Rep. Josh Gottheimer (D-NJ) led a group of eight other Democrats — Reps. Carolyn Bourdeaux (D-GA), Jared Golden (D-ME), Ed Case (D-HI), Jim Costa (D-CA), Kurt Schrader (D-OR), Filemon Vela (D-TX), Henry Cuellar (D-TX) and Vicente Gonzalez (D-TX) — in sending a letter last week threatening to withhold their votes on the budget resolution until the Senate-passed bipartisan package is signed by the President.

So far, Democratic leadership has brushed off the attempt — House Speaker Nancy Pelosi (D-CA) reportedly referred to it as “amateur hour” in a recent leadership call. But if the group holds firm, they could halt movement on the budget resolution, since Democrats can only afford to lose three votes on party-line issues.

“We’re all talking and trying to find a way forward,” Gottheimer told Jewish Insider on Thursday evening. “I think we’ll figure it out. And I’m really confident that we can come to a resolution to get this passed, and to move forward on reconciliation. So I believe we’ll figure out how to get there.”

It’s not clear what that path forward looks like unless one wing of the House Democratic Caucus wavers. The House Progressive Caucus announced that a majority of its 96 members — it has not provided an exact number — will not vote for the infrastructure package until the Senate passes the budget with a range of progressive spending priorities, seemingly leaving neither package with enough votes to move forward.

The New Jersey congressman, a co-chair of the bipartisan Problem Solvers Caucus, blames these colleagues for jeopardizing progress on the two spending packages.

“The real question is why are some of my colleagues holding up the President’s infrastructure package? It passed the Senate with 50 Democrats, including [Sen.] Bernie Sanders… and also 19 Republicans,” he said. “The Senate passed infrastructure one day and then 24 hours later passed the budget resolution to get the ball rolling there, officially. Now all we’re saying is let’s just do the exact same thing.”

The New Jersey congressman said he’s been receiving consistent pressure from his district to push through the bipartisan package.

“I can’t tell you how many calls I’m getting that just say, ‘Let’s get this infrastructure package done,’” he said. “It’s two million jobs a year. Local labor is calling daily — all the different unions — to get this passed as soon as possible so we can get shovels in the ground.”