For months, Mr. McCain has lamented a Senate legislative process that avoided hearings or formal bill-drafting procedures and excluded Democrats. On Friday, he said those tactics were intolerable.
“We should not be content to pass health care legislation on a party-line basis, as Democrats did when they rammed Obamacare through Congress in 2009,’’ Mr. McCain said. “If we do so, our success could be as short-lived as theirs when the political winds shift, as they regularly do.’’
A bill of this magnitude “requires a bipartisan approach,’’ Mr. McCain added.
Those concerns were compounded by the decision of Republican leaders to press forward with a vote next week before the nonpartisan Congressional Budget Office could complete a full analysis of the Graham-Cassidy legislation. The budget office is expected to estimate the cost of the bill early in the week, but it indicated that it would not be able to complete an analysis of the bill’s effects on health insurance coverage or premiums by Sept. 30.
That date is critical because Republicans, who hold 52 seats in the Senate, have until the end of this month to make use of special budget rules that would allow them to pass a repeal bill in the Senate with only a simple majority, rather than 60 votes. If Republicans could get 50 votes, Vice President Mike Pence would break the tie in their favor.
“Of course, I’m disappointed,” Mr. Cassidy said in an interview, “but that doesn’t mean that I’m going to stop working for those folks who can’t afford their premiums. We are still working. We are still hoping.”
Mr. Graham, mindful of their longstanding relationship, was gracious. “My friendship with John McCain is not based on how he votes,” Mr. Graham said, “but respect for how he’s lived his life and the person he is.”
Mr. Pence was not giving up. “President Trump and I are undeterred,” he said at a speech in Indiana.
A spokeswoman for the Senate majority leader, Mitch McConnell of Kentucky, declined to comment on whether he would press forward with a vote.
Democrats have vowed that if the repeal legislation could be killed, they would press to resume bipartisan negotiations on legislation to stabilize health insurance markets under the Affordable Care Act. Republican leaders squelched those talks, led by Senators Lamar Alexander, Republican of Tennessee, and Patty Murray, Democrat of Washington, as they pushed for passage of a full repeal bill.
“John McCain shows the same courage in Congress that he showed when he was a naval aviator,” said Senator Chuck Schumer of New York, the Democratic leader. “I have assured Senator McCain that as soon as repeal is off the table, we Democrats are intent on resuming the bipartisan process.”
If the bill dies at the hands of Senators McCain, Paul and Collins, it would be another blow to President Trump, who has tried to pressure Republicans to fall in line.
It would also be another setback for a party that now controls the White House and both houses of Congress, but has not been able to produce any major legislative achievements. Republican lawmakers have promised for seven years to repeal and replace the Affordable Care Act, but they have found that verbally assailing the health law is far easier than actually undoing it, even with a president who shares their goal.
“It’s a loss for Republicans,” said Representative Mark Walker of North Carolina, the chairman of the conservative Republican Study Committee. “I think we’re all going to be held accountable to some degree. What that means in next year’s elections, I don’t know. But this is going to bite for a while.”
The Graham-Cassidy bill would take much of the money provided under the Affordable Care Act and send it to the states, with vast discretion over how to use it for health care or coverage. The bill has been met in the last few days with a torrent of criticism from consumer groups, doctors, hospitals, insurance companies, governors and state Medicaid officials.
Under the bill, states would have more authority over how to use federal funds, but most states — including Arizona — would receive less money under the bill than under the Affordable Care Act, according to studies by the Kaiser Family Foundation and health policy consulting firms.
The bill would also give states the ability to opt out of insurance regulations under the health law. States could seek federal waivers that would allow insurers to charge higher premiums to people with pre-existing medical conditions or to omit certain benefits that they are now required to provide, such as maternity care or mental health care.
Republican leaders will now likely have to change an opponent’s mind, but if anything, more opponents could emerge, with Ms. Murkowski on the top of the list. Alaska’s governor, Bill Walker, an independent, publicly opposes the bill and has joined nine other governors in signing a letter urging the Senate to reject the proposal. In an interview, Mr. Walker said he did not believe any special accommodation could be reached for his state, because the overall structure was so damaging to Alaska. He said he had communicated his concerns extensively to Ms. Murkowski.
“Alaska would fare very, very poorly,” he said. “Nothing has been brought to my attention that would increase my comfort level.”
A spokeswoman for Ms. Murkowski, Karina Petersen, said the senator is studying the matter. “Senator Murkowski is still focused on how the bill will impact Alaska, specifically,” Ms. Petersen said. “She’s continuing to gather data and is looking at the details of the bill to determine what’s best for her state.”
Gov. Doug Ducey of Arizona, a Republican, supports the Graham-Cassidy proposal, and Mr. McCain had made a point of emphasizing that he was keenly interested in the views of his state’s governor when contemplating whether to vote for repeal legislation. But Mr. Ducey’s position was not enough to sway Mr. McCain.
“I take no pleasure in announcing my opposition,” Mr. McCain said. “Far from it. The bill’s authors are my dear friends, and I think the world of them. I know they are acting consistently with their beliefs and sense of what is best for the country. So am I.”
Mr. McCain said he hoped senators would keep trying to devise a short-term bipartisan solution to some of the problems plaguing insurance markets under the Affordable Care Act. Mr. Alexander and Ms. Murray have been working on a bill to stabilize markets by providing money for subsidies paid to insurers so they can reduce out-of-pocket costs for low-income people.
Mr. Alexander, the chairman of the Senate health committee, and Ms. Murray, the top Democrat on the panel, held four hearings in two weeks and were nearing an agreement on legislation. But their efforts were derailed when the White House and Senate Republican leaders pushed hard for a vote on the Graham-Cassidy bill, in the face of opposition from every Democrat in the Senate.