WASHINGTON — Senator Susan Collins of Maine said on Monday that she would oppose the latest plan to repeal and replace the Affordable Care Act, leaving Republican leaders clearly short of the votes they need for passage.
Ms. Collins, a Republican, announced her opposition in a written statement, delivering a significant and possibly fatal blow to the party’s seven-year quest to dismantle the health law.
“Health care is a deeply personal, complex issue that affects every single one of us and one-sixth of the American economy. Sweeping reforms to our health care system and to Medicaid can’t be done well in a compressed time frame, especially when the actual bill is a moving target,” Ms. Collins said in the statement.
“Today, we find out that there is now a fourth version of the Graham-Cassidy proposal, which is as deeply flawed as the previous iterations,” she said. “The fact that a new version of this bill was released the very week we are supposed to vote compounds the problem.”
She added: “This is simply not the way that we should be approaching an important and complex issue that must be handled thoughtfully and fairly for all Americans.”
The announcement came three days after Senator John McCain, Republican of Arizona, said that he could not “in good conscience” support the latest repeal proposal, written by Senators Lindsey Graham of South Carolina and Bill Cassidy of Louisiana. The senators released a revised version of their bill on Monday morning, hoping to win over holdout Republicans in part by shifting more funds to states like Maine and Alaska.
Mr. McCain, who killed the last repeal effort in July with a dramatic middle-of-the-night vote, faulted Republicans for trying to pass sweeping health care legislation without the participation of Democrats or fulsome public deliberations about the undertaking.
Senator Rand Paul, Republican of Kentucky, had previously said he would oppose the Graham-Cassidy bill on the grounds that it did not go far enough in repealing the health law. A spokesman for Mr. Paul said on Monday that the senator’s position had not changed.
Senator Ted Cruz, Republican of Texas, said on Sunday that he had not yet been won over and was seeking changes to the repeal plan. An aide to Mr. Cruz said on Monday that his position remained the same.
Adding urgency to the matter, Republicans have until Sept. 30 to make use of special budget rules under which they can pass a repeal bill with only a simple majority, rather than needing Democratic votes. Even with those expedited procedures, Republicans can afford to lose only two of their 52 members, with Vice President Mike Pence breaking the resulting tie.
On Monday, President Trump expressed frustration that Republicans had talked for years about repealing and replacing the Affordable Care Act but had failed to deliver now that a Republican was in the White House.
Mr. Trump singled out Mr. McCain for his decisive vote in July, and he seemed resigned to defeat this week.
“We’re going to lose two or three votes, and that’s the end of that,” the president said on the “Rick & Bubba Show,” a radio program.