President Joe Biden’s legislative agenda is being squeezed from both ideological wings of his party, creating a huge headache for Democratic leaders as they race to overhaul the nation’s infrastructure and pass other social programs.

On the one side, a group of moderate House Democrats is demanding House Speaker Nancy Pelosi (D-Calif.) schedule a vote on the Senate-passed bipartisan $1.2 trillion infrastructure bill as soon as possible ― before turning to a $3.5 trillion partisan spending measure dealing with climate, health care, housing and more. Like their counterparts in the Senate, the moderate House lawmakers do not support a package of such size.

On the other side, progressive lawmakers are threatening to vote against the bipartisan infrastructure bill, which they view as insufficient to solving growing threats like climate change, without passage of the additional $3.5 trillion bill Democrats plan to advance on their own through a special budgetary process called reconciliation.