Senate Republicans and Sen. Joe Manchin voted to roll back an EPA regulation on truck pollution.
The legislation, which Biden has vowed to veto, passed 50-49.
Democratic Rep. Ro Khanna argued it wouldn’t have passed had Sen. Dianne Feinstein been present.
In a 51-49 split Senate, every vote matters.
Senate Republicans and Democratic Sen. Joe Manchin took advantage of Democratic Sen. Dianne Feinstein’s ongoing medical leave to roll back a significant environmental regulation on Wednesday.