Sen. Joe Manchin (D-WV) won’t support provisions in Democrats’ proposed economic legislation that would allocate spending toward climate change or increase taxes for the wealthy.

The announcement, following months of negotiations, deals a blow to Democrats as they attempt to advance a key part of their agenda before the midterm elections in November when their majorities in Congress are at risk. Manchin, who is not up for reelection this cycle, blasted the left-wing members of his party for prioritizing “political headlines” over “economic realities.”