WASHINGTON — Senate Republican leaders, facing their restive colleagues after the Fourth of July recess, vowed on Tuesday to press ahead with their effort to repeal and replace the Affordable Care Act, with a new version of their bill on Thursday and a vote next week — regardless of the deep divisions in the party.
The weeklong recess only seemed to generate more doubts about the Senate bill, but Senator Mitch McConnell of Kentucky, the majority leader, signaled that he was not ready to give up on his party’s seven-year-old promise to gut President Barack Obama’s signature domestic achievement. Accusing Democrats of obstructionism, he announced he would delay the Senate’s scheduled August recess by two weeks so that senators could keep working.
But pessimism among Republicans still pervaded the Capitol on Tuesday after a week in their home states that did little to resolve the disputes that thwarted a vote last month.
Senator Charles E. Grassley, Republican of Iowa, said Tuesday that he was “very pessimistic” about passing a bill, while Senator John McCain, Republican of Arizona, said it was “very possible, very probable” that the Senate bill was dead.
Senator Susan Collins, Republican of Maine, said, “Minor changes and tweaks will not be sufficient to win my support for the bill.”
Changes are coming, but none that are likely to radically alter the estimate by the Congressional Budget Office that 22 million fewer people would have health insurance in 2026 under the Senate health care bill than under the Affordable Care Act. A new estimate is expected from the budget office early next week.
The revised bill is expected to include a $45 billion fund to help combat the opioid epidemic, as well as a provision allowing consumers to use health savings accounts to pay for premiums.
Senate Republicans are also likely to keep a pair of taxes imposed by the Affordable Care Act on people with high incomes. The law increased the payroll tax rate for many high-income taxpayers and imposed a tax on their investment income. Both taxes would be eliminated by the repeal bill passed by the House in May and by the original version of Mr. McConnell’s bill.
Keeping those taxes would undercut a major argument against the bill by Democrats, who have branded it as a tax cut for the rich disguised as a health bill.
But the largest changes to the health care system are likely to remain in the bill. About two-thirds of the increase in the projected number of uninsured Americans would result from deep cuts in expected Medicaid spending, the budget office said. The bill would impose caps on Medicaid spending and would roll back the expansion of the program under the Affordable Care Act.
The Senate measure will be considered under special procedures that limit debate to 20 hours, preclude a Democratic filibuster and allow passage with a simple majority vote. It is unclear whether Mr. McConnell would start the debate next week if he lacks firm commitments from enough senators to ensure passage.
Delaying the vote — again — might not help.
“Anybody who thinks that it’s going to get easier by waiting,” said Senator John Kennedy, Republican of Louisiana, “that’s a testament to the power of human denial as far as I’m concerned.”
At least 10 Republican senators, led by David Perdue of Georgia, had urged the majority leader to work into the month of August, so lawmakers could show some results to their constituents.
Mr. McConnell said delaying the recess would provide time to work on other matters after the Senate deals with health care next week. But the Senate Democratic leader, Chuck Schumer of New York, suggested a different motivation for Mr. McConnell’s announcement.
“They’re struggling with health care,” Mr. Schumer said. “They don’t want to go home and face their constituents.”
“The problem is not the timing,” he added. “It’s the substance.”
Senate Republicans are still skirmishing over a proposal by Senator Ted Cruz, Republican of Texas, that would allow insurers to sell stripped-down insurance policies if they also offered at least one plan that complied with federal insurance standards under the Affordable Care Act. Under this proposal, insurers could, for example, omit coverage of certain services like maternity care or mental health care.
Mr. Cruz says his proposal would give consumers new, lower-priced insurance options. On Tuesday, he called it “the necessary ingredient to getting the votes” to repeal the health law.
“I believe we can get there,” he said. “It remains challenging. More work remains to be done. But there is a path forward, and that path revolves around lowering premiums.”
But Mr. Cruz’s proposal underscored the problem that Mr. McConnell faces: Making a change to please some Republican senators could alienate others. With Democrats united in opposition, he can afford only two Republican “no” votes.
Ms. Collins, who is already dissatisfied with the Senate bill, warned about the potential negative consequences of the Cruz amendment. Critics of his proposal say it would create two insurance markets: an inexpensive one for the young and healthy, and another, far more expensive one for sick and older Americans that could price those with pre-existing medical conditions out of the market.
“If it is as described,” Ms. Collins said, “I believe it would further destabilize the individual markets, undermine the protections for people with pre-existing conditions and cause premiums to increase for people with pre-existing conditions.”
“I certainly don’t think that that is the answer,” she added.
Also on Tuesday, the Trump administration approved a waiver sought by the state of Alaska for an innovative program to help stabilize the individual insurance market.
The state, which has exceptionally high health care costs and insurance premiums, has established a “reinsurance program” to help pay claims for consumers with certain very high-cost medical conditions like metastatic cancer, H.I.V. and AIDS.
The House and Senate bills would provide tens of billions of dollars for such programs, intended to help keep premiums down and encourage more insurers to participate in the market.