Senate Majority Leader Mitch McConnell, R-Ky., said Thursday that if his party fails to muster 50 votes for its plan to rewrite the Affordable Care Act, it will have no choice but to draft a more modest bill with Democrats to support the law’s existing insurance markets.

The remarks, made at a Rotary Club lunch in Glasgow, Kentucky, represent a significant shift for the veteran legislator. While he had raised the idea last week that Republicans may have to turn to Democrats if they cannot pass their own bill, his words mark the first time he has explicitly raised the prospect of shoring up the ACA.

“If my side is unable to agree on an adequate replacement, then some kind of action with regard to the private health insurance market must occur,” McConnell said. “No action is not an alternative. We’ve got the insurance markets imploding all over the country, including in this state.”

McConnell, who pledged in 2014 to eradicate the law also known as Obamacare “root and branch,” initially raised the prospect of having to work with Democrats last week after he pulled a measure he had crafted behind closed doors. That bill would jettison the ACA’s requirement that most individuals prove they have health coverage, would repeal or delay billions in taxes imposed under the current law and would make deep, long-term cuts to the nation’s Medicaid program.

But while he previously declared that Republicans “need to come up with a solution” if they wanted to make real changes to the nation’s health-care system, McConnell on Thursday acknowledged how difficult it is proving to craft an alternative that can satisfy the GOP’s conservative and centrist camps.

His suggestion that he and his colleagues might instead try to bolster the insurance exchanges created under the ACA is at odds with Republican talking points that they are beyond repair. The marketplaces were built for people who do not have access to affordable coverage through a job, and at last count slightly more than 10 million Americans had health plans purchased through the exchanges. More than 8 in 10 customers bought their plans with federal subsidies the law provides.

Until now, both congressional Republicans and the Trump administration have contended that the “collapse” of the ACA marketplaces is a main reason to erase much of the 2010 law.

Mitch McConnell, above on Capitol Hill in June, acknowledged on Thursday how difficult it is to craft an alternative health-care bill that can satisfy the Republicans’ conservative and centrist camps. Washington Post /Jabin Botsford

McConnell said Thursday in Glasgow that he continues to “twist the dial” to build support for his legislation. But with no Democrats willing to back it, he can lose no more than two of his 52 caucus members. Vice President Mike Pence would then cast the tiebreaking vote.

A spokesman said Thursday evening that there was “literally” no difference between McConnell’s remarks this week and last week, when he said that “either Republicans will agree and change the status quo, or the markets will continue to collapse and we’ll have to sit down” with Democrats.

“Both times he was talking about passing something,” Don Stewart said. “His point was: The only way Democrats would work with us is [to] prop up Obamacare, not fix it.”

Yet the Fourth of July recess has not bolstered the political prospects for McConnell’s legislation; Republican senators have been peppered with questions by constituents anxious about the potential impact on their coverage. In the past several days, some senators have implied that considerable work would still be required before the Better Care Reconciliation Act could pass the Senate.

Sen. Patrick Toomey, R-Pa., a conservative who has played a key role in the chamber’s health-care negotiations this year, said Wednesday during an appearance before a live audience at WHTM-TV in Harrisburg, Pennsylvania, “We’re still several weeks away from a vote, I think.”

This week, Sen. Ted Cruz, R-Texas, who opposed McConnell’s original draft bill, also voiced skepticism about the chances of Republican senators coming together and passing a bill.

At a town hall hosted by a conservative group north of Dallas on Wednesday evening, Cruz said he was “not certain” whether Republicans would be able to repeal the law. “I hope we will. I believe we will,” he added. On Thursday, Cruz said in an interview with KTSA radio in San Antonio that though he was feeling hopeful, “I don’t know if we get it done or not.” The situation, he said, “is precarious.”

Meanwhile, Sen. Jerry Moran, R-Kan., told a town hall meeting in rural Palco that “there are people who tell me they are better off” with the ACA, “and I believe them.” Moran, who said last week he did not support the Republican measure in its current form, called for “a national debate that includes legislative hearings. . . . It needs to be less politics and more policy.”

President  Trump has repeatedly pronounced the ACA “dead.” And in contrast with their predecessors in the Obama administration, who talked up the law’s marketplaces, Health and Human Services officials have been issuing maps, detailing in red the number of U.S. counties in danger of being without marketplace offerings for 2018. The most recent map, released Wednesday, showed 40 “bare” counties in Ohio, Indiana and Nevada.

This naysaying is at odds with official forecasts of the marketplaces’ likely future. In estimating the effects of McConnell’s bill, the Congressional Budget Office said that, if the ACA were left intact, its exchanges would remain “stable in most areas.”

The forecast noted that “a small number of people” live in parts of the country in which few insurers have been interested in selling individual policies. Some of the companies now may withdraw, in part because of the changes that Republicans have been considering. Those include eliminating the ACA’s requirement that most Americans carry health insurance and abolishing $7 billion in cost-sharing subsidies that have helped lower-income consumers afford their health plans’ deductibles and copays.

Senate Minority Leader Charles Schumer, D-N.Y., on Thursday called McConnell’s statement “encouraging” and said his caucus is “eager to work with Republicans to stabilize the markets and improve the law. At the top of the list should be ensuring cost-sharing payments are permanent, which will protect health care for millions.”

But there has been no outreach yet from Republican Senate leaders to their Democratic counterparts, and the two parties remain far apart in terms of which policy solutions each prefers when it comes to revamping the ACA. Still, more than half a dozen rank-and-file members from both parties huddled privately in May to discuss finding common ground.

Among those were some of the most outspoken Republican critics of McConnell’s bill, such as Shelley Moore Capito (W.Va.), Susan Collins (Maine) and Bill Cassidy (La.), as well as Democrats such as Joe Donnelly (Ind.), Heidi Heitkamp (N.D.) and Joe Manchin III (W.Va.).

Before the recess, Heitkamp said in an interview that she would be telling constituents that she remained open to bipartisan negotiations – if certain conditions are met.

“The real thing here is making sure people understand that there are choices,” she said. “That we can fix what’s wrong with the Affordable Care Act without taking away Medicaid for disabled kids. That we can fix what’s wrong with the Affordable Care Act without giving billions of dollars of tax breaks to the wealthiest among us. That we have an opportunity to work together here if we can figure out how to collaborate. And that the way to do it is not in some backroom; the way to do it is in a markup in a hearing with regular order.”

The Washington Post’s Ed O’Keefe and Sean Sullivan contributed to this report.