The Democratic Party’s left flank is firmly united with moderate Democrats behind the goal of ousting Trump, with former Bernie Sanders aides and allies creating super PACs and promising to spend millions to elect Biden in a way they never did for Clinton. But progressives, who are emboldened after successfully ousting several entrenched Democrats in recent primaries, are also clear: Unlike with Obama, there will be no honeymoon for Biden.

If they follow through, Biden’s ability to cut deals with Republicans — a central pledge of his campaign — would be hemmed in from day one.

Signs are everywhere that progressives are unbowed. Former staffers to Charles Booker, who came close to defeating establishment pick Amy McGrath in Kentucky’s Senate primary this year, are making plans to create a group to help put progressives in the chamber. Top “Medicare for All” activists are in talks about forming a PAC to put single-payer advocates in office and fight the policy’s enemies. A Freedom Caucus for the left is being discussed. And even before they’ve defeated Trump, progressives are warning Biden that he — or his running mate Sen. Kamala Harris (D-Calif.) — might be challenged in the 2024 primary if they’re not sufficiently progressive.

“Our movement is ascendant,” said Joseph Geevarghese, executive director of the Sanders-founded group Our Revolution. “The risk that Biden or Harris faces is a challenge from the left in 2024 if they govern as Third Way-ers or do Clinton-esue triangulation.”