WASHINGTON — As divisions between the two main ideological camps within the GOP widened Tuesday, Republicans were scrambling to contain the political fallout from the collapse of a months-long effort to rewrite Barack Obama’s signature domestic accomplishment.

President Donald Trump predicted Tuesday morning that Republicans may wait for the federal insurance market to collapse and then work to broker a deal to rewrite the nation’s landmark health care law, while Senate leaders pressed ahead with a plan to repeal the Affordable Care Act with no immediate replacement.

But it became quickly apparent that GOP leaders, who were caught off guard by defections of their members, lacked the votes to abolish parts of the 2010 law outright. Three centrist Republican senators — Susan Collins, Maine, Shelley Moore Capito, West Virginia, and Lisa Murkowski, Alaska — all said they would oppose any vote to proceed with an immediate repeal of the law.

“I did not come to Washington to hurt people,” Capito said on Twitter. She added, “I will only vote to proceed to repeal legislation if I am confident there is a replacement plan that addresses my concerns.”

Collins said in a statement that she had urged Senate Health, Education, Labor and Pensions Committee Chairman Lamar Alexander, R-Tennessee, to hold hearings in an attempt to fashion a new legislative fix for the ACA, while leaving it in place in the meantime.

“We can’t just hope that we will pass a replacement within the next two years,” she said. “Repealing without a replacement would create great uncertainty for individuals who rely on the ACA and cause further turmoil in the insurance markets.”

Trump, for his part, blamed the demise of a plan to rewrite the ACA on Democrats “and a few Republicans,” but he suggested that the drive to overhaul the law was not completely over.

Speaking to reporters in the Roosevelt Room on Tuesday afternoon, Trump said he was “disappointed” in the demise of the Senate bill. Now his plan is “to let Obamacare fail; it will be a lot easier,” he said. “And I think we’re probably in that position where we’ll let Obamacare fail.”

“We’re not going to own it. I’m not going to own it,” the president said. “I can tell you the Republicans are not going to own it. We’ll let Obamacare fail, and then the Democrats are going to come to us.”

Trump’s latest comments intensified the current political uncertainty on Capitol Hill, where GOP leaders were debating what to do next, and they raised anxiety among insurers that must commit to staying on the federal health exchange within a matter of weeks.

Republicans are reeling after two more GOP senators declared their opposition Monday to the party’s plan to overhaul the nation’s health care system, likely ending their quest to make good on a GOP promise that has defined the party for nearly a decade and has been one of Trump’s top priorities.

Senate Majority Leader Mitch McConnell, R-Kentucky, opened the Senate on Tuesday morning touting his latest plan — to vote on a pure repeal, with a two-year delay, by taking up the House’s health care bill.

But Senate Majority Whip John Cornyn, R-Texas, didn’t even try to project confidence that the pure repeal vote would succeed, a further sign that it is little more than an exercise to dare members and demonstrate publicly that there is little appetite for such a move.

“We will find out,” he said Tuesday morning when asked if leaders had the votes for it to work.

And in a sign of the extent to which Senate leaders have lost control of the process, Cornyn, whose job is to count votes, said he had “no idea” that Sen. Mike Lee, R-Utah, was suddenly going to join Sen. Jerry Moran, R-Kansas, in defecting Monday night.

Cornyn learned about it that night “a little after 8 o’clock,” he said, after he and six other GOP senators dined with Trump at the White House.

As Republicans tried to regroup, Senate Minority Leader Charles E. Schumer, D-New York, renewed his calls for the majority to work with Democrats to shore up the health insurance system.

“It should be crystal clear to everyone on the other side of the aisle that the core of the bill is unworkable. It’s time to move on. It’s time to start over,” he said. “Rather than repeating this same, failed partisan process again, Republicans should work with Democrats on a bill that lowers premiums, provides long-term stability to the insurance markets and improves our health care system.”

“Now that their one-party effort has largely failed, we hope they will change their tune,” he said, noting that some Republicans have been calling for bipartisan talks.

Schumer quoted Sen. John McCain, R-Arizona, who said Monday night that “Congress must return to regular order” and rewrite the health care legislation with input from both parties.

“The door to bipartisanship is open now. Republicans only need to walk through it,” Schumer said.

As Schumer spoke on the Senate floor, Sen. Joe Manchin III, D-West Virginia, one of the few in the chamber who has tried to be a bipartisan broker, was placing calls to fellow senators who, like him, are former governors — a total of 11 senators including Alexander, John Hoeven, R-North Dakota, Mike Rounds, R-South Dakota, Angus King, I-Maine, Jeanne Shaheen, D-New Hampshire, and Maggie Hassan, D-New Hampshire. Aides said Manchin was presenting nothing specific yet to his colleagues, just a plea to “sit down and start bipartisan talking.”

Still, the White House and congressional leaders tried to press ahead Tuesday with a single-party solution.

Vice President Mike Pence, speaking at the National Retail Federation’s annual Retail Advocates Summit, challenged Congress to “step up” and repeal the current law “so that lawmakers can “work on a new health care plan that will start with a clean slate.”

And McConnell declared on the Senate floor, “This doesn’t have to be the end of the story.”

McConnell said the Senate would next take up “a repeal of Obamacare combined with a stable two-year transition period.” He said that President Obama had vetoed such legislation before but that “President Trump will sign it now.”

While he noted that the measure had overwhelming support among Republican senators in 2015, the Senate leader also acknowledged that his party has suffered a political setback.

“I regret that the effort to repeal and immediately replace the failures of Obamacare will not be successful,” he said. “We will now try a different way to bring the American people relief from Obamacare.”

The sudden breaks by Lee, a staunch conservative, and Moran, a McConnell ally, rocked the GOP leadership and effectively closed what already had been an increasingly narrow path to passage for the bill.

They joined Sens. Rand Paul, Kentucky, and Collins, who also oppose the latest health care bill. With just 52 seats, Republicans can afford to lose only two votes to pass their proposed rewrite of the ACA. All 46 Democrats and two independents are expected to vote against it.

Lee supports the idea of moving ahead with a straight repeal of the existing law, and his spokesman, Conn Carroll, said Tuesday he would back a motion to proceed on a bill that would achieve that aim. But many centrist Republican senators have said they oppose dismantling key aspects of the ACA without an immediate replacement, given that roughly 20 million Americans have gained coverage under the law.

The confusion over next steps highlights the predicament now faced by Republicans, who have made rallying cries against Obama’s 2010 health care law a pillar of the party’s identity. They may be forced to grapple with the law’s shift from a perennial GOP target to an accepted, even popular, provider of services and funding in many states, which could make further repeal revivals difficult.

Meanwhile, Trump and other Republicans will confront a Republican base that, despite fervent support for the president, still seeks a smaller federal government and fewer regulations.

All of these forces remained vexing factors Monday as senators bailed on the bill. And no evident solution was offered by the White House — which has been limited in its sale of the GOP plan — or from McConnell, for how to bring together a party in which moderates and conservatives are still deeply divided over the scope of federal health care funding and regulations.

In many ways, the leadership plan did not go far enough for those on the right, but was too radical for GOP centrists. It scaled back some key ACA requirements and made deep cuts over time in Medicaid, but preserved popular provisions of the law such as a ban on denying coverage to consumers with costly medical conditions.

But the fact that it would reduce federal Medicaid funding and phase out the program’s expansion in 31 states and the District of Columbia rankled several key GOP governors and senators, who feared that their states would be saddled with the unpalatable choice of either cutting off constituents’ health coverage or facing a massive new financial burden.

The opposing pressures have left McConnell in a tough position as he has struggled to find a solution, which is why he has now thrown out the idea of moving to an immediate repeal.

Abolishing several of Obamacare’s central pillars — including the mandate that taxpayers buy coverage, federal subsidies for many consumers’ premiums and Medicaid coverage for roughly 11 million Americans — could wreak havoc in the insurance market. A Congressional Budget Office analysis in January estimated that premiums in the individual insurance market would rise between 20 and 25 percent next year and would roughly double by 2026.

At the same time, according to the CBO, the number of uninsured would spike by 18 million next year and rise to 32 million by 2026.

“For insurers, the worst possible outcome in this debate has always been a partial repeal with no replacement, which is exactly what Congress is about to take up,” said Larry Levitt, senior vice president for special initiatives at the Kaiser Family Foundation, in an email. “Insurance companies would be on the hook for covering people with pre-existing conditions, but with no individual mandate or premium subsidies to get healthy people to sign up as well.”

While pursuing an immediate repeal would please conservatives, the fact that it lacks sufficient support leaves McConnell and House Speaker Paul D. Ryan, R-Wisconsin, with few good options.

Another move, which McConnell threatened recently, would be to work with Democrats to prop up the insurance exchange markets that have been imploding in some states — which probably would win passage but would infuriate the conservative base that has been calling for the end of the Affordable Care Act.

But Ryan showed little interest Tuesday in making common cause with Democrats, telling reporters that House leaders “would like to see the Senate move on something” to keep the repeal-and-replace process alive.

In a closed-door conference meeting, according to several members present, Ryan told colleagues that the ball remains in the Senate’s court and announced no plans for further action on health care in the House. He also urged House members to be patient and not to openly vent frustration with the Senate, the members said.

Publicly, he emphasized that the Senate had “a razor-thin majority” and that passing legislation is “a hard process.”

Speaking to reporters Tuesday, Sen. Marco Rubio, R-Florida, said senators’ willingness to deny Trump one of his top priorities has less to do with the president’s political standing and more with home state pressures, “whether it’s their governors, or the way health care is structured in their individual states.”

“This is the Senate. Leadership sets the agenda, but senators vote in the interests of their states,” Rubio added. “Republics are certainly interesting systems of government. But certainly better than dictatorship.”

The Washington Post’s Ed O’Keefe, Mike DeBonis and Kelsey Snell contributed to this report.