A previously united front of Democratic opposition in the U.S. Senate began to break this week as three Democrats crossed party lines to back a Republican proposal aimed at reopening the federal government.

The shutdown, now in its seventh day, is nearing the point when federal workers will begin missing paychecks, intensifying pressure on both parties to reach an agreement before furloughed employees face financial hardship.

As recently as Monday, Senate Minority Leader Chuck Schumer (D-NY) had urged his caucus to “fight” to preserve Affordable Care Act subsidies, which Republicans have proposed addressing in separate legislation.

Ongoing gridlock has so far prevented Senate Majority Leader John Thune (R-SD) from securing the 60 votes required to advance a short-term government funding measure. However, signs of potential compromise emerged Tuesday when Sens. John Fetterman (D-PA), Catherine Cortez Masto (D-NV), and Angus King, a Maine Independent who caucuses with Democrats, continued to side with Republicans in supporting a clean spending plan,