Sen. Susan Collins (R-ME) confirmed Monday night that she will vote against her own party’s motion to proceed on a bill that would repeal much of the Affordable Care Act, cut hundreds of billions of dollars from Medicaid, and trigger insurance coverage loss for 22 million people over the next 10 years.

I want to work w/ my GOP & Dem colleagues to fix the flaws in ACA. CBO analysis shows Senate bill won't do it. I will vote no on mtp. 1/3 — Sen. Susan Collins (@SenatorCollins) June 26, 2017

Speaking to reporters earlier on Monday night, Collins was non-committal on her vote, saying only that the Congressional Budget Office analysis of the bill released earlier Monday was “obviously not positive.”

In subsequent tweets, she noted that “1 in 5 Mainers are on Medicaid” and would be severely impacted by the deep cuts in the bill. “Medicaid cuts hurt most vulnerable Americans; access to healthcare in rural areas threatened,” she wrote.

Senate bill doesn't fix ACA problems for rural Maine. Our hospitals are already struggling. 1 in 5 Mainers are on Medicaid. 3/3 — Sen. Susan Collins (@SenatorCollins) June 26, 2017

Collins’ announcement comes on the heels of Sen. Rand Paul (R-KY) announcing that he will also vote no on the motion to proceed. Unlike Collins, who feels the bill goes too far in gutting Medicaid spending and rolling back protections for the sick and elderly, Paul slammed the legislation for not going far enough.

Several other GOP lawmakers critical of the bill have also suggested they may oppose the motion to proceed, which would stop the effort in its tracks. These “maybes” include Sen. Dean Heller (R-NV) and Sen. Ron Johnson (R-WI), whose concerns range from the bill’s rushed and secretive process to its impact on their constituents.