A handful of Republican senators are attempting to revive the healthcare repeal effort that appeared all but dead and buried when Congress left Washington for the summer.

The last-gasp effort is gaining momentum on Capitol Hill as Republicans confront a narrowing window in which to dismantle Barack Obama’s Affordable Care Act (ACA) on a party-line vote.

The legislation, authored by senators Lindsey Graham, Bill Cassidy, Ron Johnson and Dean Heller, would transfer billions of dollars currently spent on Medicaid expansion and tax credits under the ACA to states in the form of block grants. Such lump sums would be calculated with a complex formula that includes factors such as cost of living and population density.

Under the bill, millions of Americans could lose insurance coverage as spending discretion is handed to the states. The proposal also includes severe cuts to Medicaid, the national insurance program for low-income families, and would allow states to waive ACA protections that prohibit insurers from charging higher premiums of people with pre-existing conditions.

Donald Trump, frustrated with the party’s failure to repeal his predecessor’s healthcare reform, said he “applauds” the latest effort and “sincerely hopes that senators Graham and Cassidy have found a way to address the Obamacare crisis”.

Reconciliation, the process that allows lawmakers to pass budget legislation with a simple majority, expires on 30 September. After that, budgetary legislation must clear a 60-vote threshold, making it far more unlikely that Republicans will win enough votes to dramatically restructure the ACA. Democrats agree the law has problems but have so far remained unanimously against repeal.

The bill does not bridge the ideological divisions that felled previous attempts. But those behind it are painting it as a last chance to make good on seven years of promises to tear down the ACA.

“It should have been our first bill to repeal and replace Obamacare, but it is now our last,” Graham said last week at a news conference. “To those in the Republican party who feel like we have not fought as hard as we could, you’re right.”

Democrats and liberal groups are urging activists to take the effort seriously. The Senate minority leader, Chuck Schumer, warned that the new effort is a “red siren moment for the entire country”.

“No matter how many ways Republicans try to dress it up, this bill is even more dangerous than it’s predecessors,” Schumer said during a press conference on Monday.

Ben Wikler, Washington director of MoveOn, which rallied opposition to previous repeal bills, said: “Danger real. Activism needed.” Activists are preparing to flood lawmakers’ phone lines and mount protests against Republican senators in Washington and in their states this week.

The Congressional Budget Office, a nonpartisan scoring agency, must complete a cost and coverage impact analysis. David Popp, a spokesman for the Senate majority leader, Mitch McConnell, confirmed that the leader had asked the agency to “prioritize” the Graham-Cassidy bill. The bill’s sponsors will continue to cajole their colleagues at staff briefings, Popp said, as leaders gauge support. In response to the request, Democrats sent a letter to the CBO demanding a “full assessment” of the legislation before the bill comes to the floor.

“A comprehensive CBO analysis is essential before Republicans force a hasty, dangerous vote on what is an extreme and destructive repeal bill,” the group of Democratic lawmakers wrote.

Senator John McCain, who derailed the last repeal effort, says he does not see ‘any possibility’ of supporting this measure in its current form. Photograph: Cliff Owen/AP

Graham and Cassidy have said they are close to getting the requisite 50 votes – Vice-President Mike Pence would break the tie – but that was said of each bill that has failed so far.

At least one Republican is firmly against the bill. Rand Paul, a Kentucky libertarian who wants a full repeal of the ACA, said the measure keeps “90% of the spending of Obamacare and reshuffles it”.

“It just looks like the Republicans are taking the money from the Democratic states and giving it to the Republican states but we’re keeping most of Obamacare,” Paul told a group of reporters in his office on Monday.

John McCain, the Arizona Republican whose opposition derailed the most recent healthcare proposal in a late-night vote in July, has expressed an openness to the plan while saying the bill should be properly vetted in committee and attract bipartisan support. He added that he does not see “any possibility” of supporting this measure in its current form.

On Monday, McCain said that he may “reluctantly” support the measure but remains “very disturbed” by the disregard for the traditional legislative process, which allows for committee hearings, amendments and debate.

Estimating the cost and coverage impact will take “at least several weeks”, the budget office said on Monday, noting that it would release a “preliminary assessment” early next week. Responding to the news, Schumer said it would “outrageous” for Republican leadership to push forward without a full analysis.



Later Monday, the Senate finance committee announced it would hold a hearing on the Republican bill early next week, perhaps paving the way for McCain’s expression of support. The Senate homeland security and governmental affairs committee, which Johnson chairs, will also hold a hearing.

Governor John Kasich of Ohio, a Republican who has opposed his party’s healthcare efforts and urged bipartisanship, tweeted on Sunday: “I agree with my friend [McCain]: a sustainable solution to healthcare requires a bipartisan solution & regular order.”