WASHINGTON — In a potentially game-changing move, four conservative senators quickly announced Thursday afternoon that they oppose the health care bill rolled out by Republican Senate leadership earlier in the day.

Sens. Rand Paul, R-Ky.; Mike Lee, R-Utah; Ted Cruz, R-Texas and Ron Johnson, R-Wis. said in a statement that the proposal did not go far enough to overhaul the current system.

“There are provisions in this draft that represent an improvement to our current health care system, but it does not appear that this draft as written will accomplish the most important promise that we made to the Americans: to repeal Obamacare and lower their health care costs,” the group said in the release.

With only 52 Republican senators, the bill will fail if the four legislators maintain their opposition. But the senators indicated that they would be open to a revised version of the bill. This means they may attempt to force concessions from Senate Minority Leader Mitch McConnell, R-Ky., before the bill is brought to a vote — possibly as soon as next week.

“We are open to negotiation and obtaining more information before it is brought to the floor,” the statement said.

Paul and Lee have been critical of the drafting process in recent days, saying it lacked transparency and indicating that they were not entirely pleased with the final outcome.

Lee and Cruz were part of the 13-member group tasked with drafting the legislation.

“The American people need and deserve to be able to see legislation as it moves through the Senate,” Lee said in a video this week.

Paul has criticized party leadership for having “forgotten” their pledge to repeal Obamacare.

“I mean, we had thousands of people standing up and cheering us on, saying they were going to repeal [Obamacare],” Paul told Bloomberg on Wednesday. “And now they’ve gotten kind of weak-kneed and I think they want to keep it.”

Sen. Mike Lee (R-UT) (2nd L) heads for his party’s weekly policy luncheon at the U.S. Capitol May 16, 2017 in Washington. Many Republican and Democratic senators expressed frustration and concern about how President Donald Trump may have shared classified intelligence with the Russian foreign minister last week at the White House. (Photo: Chip Somodevilla/Getty Images)

Meanwhile, more moderate Republicans are also skeptical about the bill. These members have expressed reservations about the legislation’s ability to roll back Medicaid expansion and defund Planned Parenthood.

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Sen Rob Portman, R-Ohio, are among the members who have advocated most strongly to preserve the Medicaid expansion parts of Obamacare. In an attempt to appease this group, the bill begins phasing out the expansion in four years rather than the previously proposed three.

But it is possible that other changes to the program remain issues.

“I have serious concerns about the bill’s impact on the Nevadans who depend on Medicaid,” Sen. Dean Heller, R-Nev., said.

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A spokesperson for Sen. Susan Collins, R-Maine, said the senator was reviewing the legislation and would wait to see the Congressional Budget Office’s report, which is expected early next week.

Another issue is the bill’s defunding of Planned Parenthood for a year. Collins has previously said that “it is a mistake” to attach funding for the health care provider to the bill, and another lawmaker, Sen. Lisa Murkowski, R-Alaska, reportedly pledged to a constituent that she would not vote to defund Planned Parenthood. Both senators reiterated those stances Thursday.

But some conservative Republican lawmakers in both the Senate and the House may bail if the Planned Parenthood provisions were dropped. The House bill, called the American Health Care Act, also defunded Planned Parenthood, and it is unclear whether many lawmakers there would support a bill that did not cut funding for the group.

Other members may object to the funding the bill would allocate combat the opioid abuse epidemic. The Senate legislation offers $2 billion in 2018 to provide grants to states on the issue — a fraction of the amount pushed for by some lawmakers, including Republicans. Portman and Sen. Shelley Moore Capito, R-W.V., asked for a larger package: $45 billion.

Capito said in a statement that she was reviewing the bill and examining whether would provide access to care for “those struggling with drug addiction.”

McConnell has indicated he would like a vote on the bill by next Thursday, before Congress goes on its July 4 recess.

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