Sen. Susan Collins delivered the likely final blow to the Senate Republicans’ latest effort to repeal and replace the 2010 health care law.

“Sweeping reforms to our health care system and to Medicaid can’t be done well in a compressed time frame, especially when the actual bill is a moving target. Today, we find out that there is now a fourth version of the Graham-Cassidy proposal, which is as deeply flawed as the previous iterations,” the Maine Republican said in a statement of the effort spearheaded by Sens. Lindsey Graham of South Carolina and Bill Cassidy of Louisiana.

“The fact that a new version of this bill was released the very week we are supposed to vote compounds the problem,” she added.

Collins became the third GOP vote in the “no” column, meaning Republicans cannot adopt the Graham-Cassidy measure even with the help of Vice President Mike Pence. Arizona Sen. John McCain and Kentucky Sen. Rand Paul are also opposed.

While Collins had been leaning against the proposal for days, she withheld formal judgment until after a bare-bones analysis from the Congressional Budget Office on Monday showed millions more would be uninsured than under the current law.

Collins also rejected the idea that Maine could be better off under the legislation.

“The fact is, Maine still loses money under whichever version of the Graham-Cassidy bill we consider because the bills use what could be described as a ‘give with one hand, take with the other’ distribution model,” she said. “Huge Medicaid cuts down the road more than offset any short-term influx of money. But even more important, if Senators can adjust a funding formula over a weekend to help a single state, they could just as easily adjust that formula in the future to hurt that state.”

Cassidy had sought to convince Collins that the block-grant approach would work to the benefit of Maine, particularly if she decided to run for governor.

He portrayed the bill as an opportunity for Collins, if she were to run for governor, to essentially create a new insurance market for the state.

“There’s going to be a billion dollars for Mainers who are lower-income to have coverage which they do not now have,” Cassidy told CNN. “Susan Collins knows a smart governor who knows insurance well, as she does, could do a heck of a lot to provide coverage for the people of Maine.”

Collins has yet to announce whether she will run for governor next year.

But speaking later with reporters, it was clear just how fundamental the Maine Republican’s concerns really were, and how much she was in alignment with the unified Democratic opposition.

“Keep in mind when the Affordable Care Act was passed, the only change that it made in the Medicaid program was to allow states the option of expanding the Medicaid program to populations that were not covered. It did not make fundamental changes in an entitlement program that had been on the books for more than 50 years,” she said. “And yet that’s what each version of this bill did, and I just don’t think you do that without extensive review and analysis.”

Even before Collins announced her final decision, Republicans seemed resigned to looking ahead to the next battles, entertaining questions about whether the next round of budget reconciliation instructions should allow for simultaneous consideration of health care overhaul and a rewrite of the tax code.

At one point, Senate Republican Conference Chairman John Thune suggested that a return to the effort to repeal the health care law could wait for the fiscal 2019 budget reconciliation process, when presumably there could be a new crop of senators elected in the 2018 midterms.

Thune said the chances for any change in course this week were slim.

“It would involve somebody having to be in a different place than they are today,” the South Dakota Republican said.

McCain, who announced Friday that his concerns about the truncated process would put him solidly against the Graham-Cassidy measure this week, had little interest in another partisan effort through budget reconciliation.

“We could avoid all that if we would sit down together and come up with a bipartisan solution, which would not give us 50 votes, it would give us 70 or 80 votes,” McCain told reporters. “I know for a fact, no matter what anybody else will tell you, that Patty Murray and Lamar Alexander can, and would like, to work together.”

The talks between Alexander and Murray, the chairman and ranking Democrat of the Health, Education, Labor and Pensions Committee respectively, had seemed promising, but they were jettisoned with the GOP move toward the Graham-Cassidy effort to largely devolve health insurance to the states.

McCain was speaking shortly before Collins made her statement, but he was not expecting to watch the scheduled Monday evening debate on CNN featuring Cassidy and Graham along with Vermont independent Sen. Bernie Sanders and Minnesota Democratic Sen. Amy Klobuchar.

“I’ll be watching the Cowboys and Cardinals,” McCain said of the Monday Night Football matchup between his homestate Arizona Cardinals and the Dallas Cowboys. “But I will record that for the archives.”

Jennifer Shutt and Ryan McCrimmon contributed to this report.