“It’s a big, complicated subject,” Senate Majority Leader Mitch McConnell said Tuesday of the Senate health care bill while expressing optimism that Republicans will come together on a deal.

WASHINGTON -- Senate Majority Leader Mitch McConnell announced Tuesday that he will delay a vote on legislation to repeal the 2010 health care law, dealing President Donald Trump a setback on a key part of his agenda.

Republican leaders had hoped to take a page from the playbook used to get a bill over the line in the House, appeasing the most conservative members of their conference while pressuring moderates to fall in line with fewer concessions.

But as opposition mounted in both camps, even against a vote to take up the bill, McConnell decided he would delay consideration until after the Senate's weeklong July Fourth recess.

"We will not be on the bill this week, but we will still be working to get at least 50 people in a comfortable place," McConnell said.

McConnell promised to revisit the legislation next month.

[INTERACTIVE: Compare House, Senate bills with Affordable Care Act]

"It's a big, complicated subject, we've got a lot of discussions going on, and we're still optimistic we're going to get there," McConnell told reporters.

The delay does not guarantee that the senators will come together. Opposition groups plan to mount pressure campaigns on lawmakers in their home states, and policy divisions are deep.

"It's hard to see how tinkering is going to satisfy my personal concerns," Sen. Susan Collins, R-Maine, told reporters.

Negotiations Tuesday that leaders hoped would move senators toward "yes" on the measure only exposed fissures in the Republican Party. Conservatives were demanding that states be allowed to waive the Patient Protection and Affordable Care Act's prohibition on insurance companies charging sick people more for coverage and are asking for a more expansive waiver system for state regulators. They also wanted more money for tax-free health savings accounts to help people pay for private insurance.

Senators from states that expanded the Medicaid program -- and Collins -- would not brook many of those changes, especially the measure to severely undermine protections for people with pre-existing medical conditions. They wanted more money for mental health benefits for people addicted to opioids and money for states to cover people left behind by the rollback of the Medicaid program in both the House and Senate versions.

Three Republican senators -- Collins, Rand Paul of Kentucky and Ron Johnson of Wisconsin -- had announced that they would vote against the motion to begin debate that had been scheduled to hit the Senate floor today, joining Sen. Dean Heller of Nevada, who made the same pledge Friday.

A bevy of other senators from both flanks of the party seemed headed in the same direction if they did not see changes made to the Senate health care bill, leaving the measure in deep peril, since Republicans can lose only two votes from their own party in order to pass it.

Pressure ramps up

The release of a Congressional Budget Office evaluation Monday did little to help leaders get votes from either side of the fence. The budget office said the Senate bill would leave 22 million more people uninsured after 10 years and reduce federal spending by $321 billion, while sending out-of-pocket medical expenses skyrocketing for the working poor and those nearing retirement.

The budget office did not provide conservatives with support for their demands, either. The state waivers already in the Senate bill "would probably cause market instability in some areas" and "would have little effect on the number of people insured" by 2026, the analysis concluded. Adding still more waivers, including one that could allow insurers to price the sick out of the health care market, could deprive even more people of health care.

Even before McConnell's decision, White House officials had braced for the likelihood that the procedural vote would fail and that they would have to revisit the measure after the July 4 recess -- when they hoped to be able to woo Johnson, who has been a fierce critic of the bill from the right. The senator has repeatedly warned that this week is too soon to vote on the health care measure, as Republican Senate leaders have insisted they need to do.

Johnson said he was "grateful" that the vote was postponed, adding that the "real deadline" would arrive when the Affordable Care Act insurance markets collapse.

Senate Minority Leader Charles Schumer, D-N.Y., said that while "the fight is not over," he was confident that Republicans would not succeed because their proposals remain unpopular with the public.

"The Republican bill is rotten at the core," Schumer said. "We have a darn good chance of defeating it, a week from now, a month from now, a year from now."

GOP leaders are now bracing for attacks from both ends of the political spectrum.

On Tuesday, Club for Growth President David McIntosh, who has clashed with Republican Party leaders in the past, issued a statement saying the proposal "restores Obamacare."

"Only in Washington does repeal translate to restore," McIntosh said. "And while it's hard to imagine, in some ways the Senate's legislation would make our nation's failing health-care system worse."

Meanwhile, other groups began laying the groundwork to attend senators' public events, while medical providers and groups representing Americans with chronic illnesses predicted that the bill could leave millions without access to adequate medical care.

Atul Grover, executive vice president of the Association of American Medical Colleges, told reporters that he and other doctors "take it personally" that the bill would lock people out of insurance for six months if they go 63 days without a health plan and try to sign up for one the next year.

"We're there at the bedside," Grover said, adding that none of his members would be willing to tell a patient: "I'm sorry about your stage-four cancer. Come back in six months, when your insurance kicks in."

Trump meeting

In the wake of the setback, Trump invited GOP senators to meet with him in the White House's East Room to discuss next steps. With Vice President Mike Pence ready to cast a tiebreaking vote on the measure, Republican leaders can lose only two of their 52 members to pass the bill, which no Democrat is willing to support.

Sitting between two of the bill's holdouts -- Collins and Sen. Lisa Murkowski of Alaska -- the president said Republicans are "getting very close" to securing the votes they need even as he acknowledged that they might fail.

"This will be great if we get it done," Trump said. "And if we don't get it done, it's just going to be something that we're not going to like -- and that's OK. I understand that very well."

In the private meeting that followed, Sen. Marco Rubio of Florida said, the president spoke of "the costs of failure, what it would mean to not get it done -- the view that we would wind up in a situation where the markets will collapse and Republicans will be blamed for it and then potentially have to fight off an effort to expand to single payer at some point."

Senators complained that the estimates provided in Monday's reports used old data about how many people were covered through the Affordable Care Act and how much their coverage cost. Others asked that the Congressional Budget Office analysts begin the process again, this time with fresh numbers.

"They're using the March 2016 insurance market," said Sen. Roy Blunt, R-Mo. "A lot of what they do is just guessing."

Pence broke off from the lunch for private meetings with Heller and Sen. Rob Portman of Ohio, who is feeling pressure from his state's governor, John Kasich, to oppose the bill and defend Ohio's Medicaid expansion.

Portman was the subject of a spirited evaluation of his open criticism of the bill by McConnell, who was frustrated with the expansion-state senators who showed their hand early to other wavering colleagues. McConnell was unhappy that Portman seemed to be abandoning his previous stance on fiscal rectitude by opposing Medicaid cuts in the bill.

But the Ohio senator was getting pressure from both sides. Kasich appeared in Washington on Tuesday to sharply criticize the Senate bill. The governor said he was deeply concerned about millions of people losing coverage under the bill.

"Who would lose this coverage?" Kasich said. "The mentally ill, the drug addicted, the chronically ill. I believe these are people that need to have coverage."

At the same news conference, Colorado's Democratic governor, John Hickenlooper, said his state's Republican senator, Cory Gardner, "understands the hardships and the difficulties in rural life."

"This bill would punish people in rural Colorado," Hickenlooper said, raising the pressure.

Doctors, hospitals and other health care provider groups came out strongly against the Senate bill, as did patient advocacy groups like the American Heart Association. The AARP also opposes it. But business groups were ramping up their support. In a letter Tuesday, the U.S. Chamber of Commerce endorsed the Senate bill and urged senators to vote for it.

The Senate bill "will repeal the most egregious taxes and mandates" of the health care law, allowing employers to create more jobs, said Jack Howard, a senior vice president of the group. The bill, he noted, would repeal a tax on medical devices and eliminate penalties on large employers that do not offer coverage to employees.

A separate letter expressing general support for the Senate's efforts was sent by a coalition of 28 business and employer groups, including the National Association of Home Builders, the National Restaurant Association and the National Retail Federation.

Information for this article was contributed by Jennifer Steinhauer, Thomas Kaplan, Robert Pear and Emmarie Huetteman of The New York Times; by Sean Sullivan, Kelsey Snell, Juliet Eilperin, Mike DeBonis, Amy Goldstein, Ed O'Keefe and David Weigel of The Washington Post; and by Erica Werner, Alan Fram, Ricardo Alonso-Zaldivar, Ken Thomas, Andrew Taylor and Michael Biesecker of The Associated Press.

A Section on 06/28/2017

Photo by The New York Times/DOUG MILLS

President Donald Trump meets with Republican senators Tuesday at the White House to discuss the next steps in the effort to pass health care legislation as party support for the latest measure fades.