Senate Majority Leader Mitch McConnell postponed a procedural vote after Republican Senator John McCain had an operation Saturday to remove a blood clot above his left eye and announced he would remain in his home state of Arizona for a week to recover.
FILE - Senate Armed Services Committee Chairman Sen. John McCain speaks on Capitol Hill in Washington, May 23, 2017.
His absence could have deprived Republicans with enough votes to even open debate on their plan to repeal and replace the Obama law, commonly known as Obamacare.
Republicans have campaigned for seven years to try to upend the Obama law, but face growing opposition. Some conservative lawmakers say the repeal effort does not go far enough to change U.S. health policies, while others say that the proposed changes would leave millions of people, many of them poorer Americans, without health insurance.
One Republican opponent of her party's plan, Senator Susan Collins of Maine, told CNN on Sunday, 'There are about eight to 10 Republican senators who have serious concern' about the Republican replacement proposal.
'I don't know whether it will pass,' Collins said, 'but I do know this, we should not be making fundamental changes in a vital safety net program that's been on the books for 50 years -the Medicaid program [with health insurance for the poor] - without having a single hearing to evaluate what the consequences are going to be.'
A new Washington Post poll showed widespread opposition to the Republican plan, with Americans preferring Obamacare by a 50-to-24 percent margin.
Until McCain's surgery, McConnell had hoped to vote on the Republican plan in the coming days. But with unified Democratic opposition to repealing Obamacare, it was questionable whether McConnell even had enough Republican votes to formally start debate on the measure, let alone pass it.
Senate Republicans need 50 votes to clear the procedural hurdle, with Vice President Mike Pence casting a tie-breaking vote if needed. Republicans hold a 52-48 majority in the Senate, but two senators - Rand Paul of Kentucky and Collins - have already said they will oppose starting debate on the proposal.
FILE - Sen. Rand Paul, R-Ky., is pursued by reporters on Capitol Hill in Washington, April 7, 2017.
McCain's absence would have left Republicans short of enough votes to advance the debate, even without other Republicans withholding their support.
In a statement on McCain, McConnell said he and his wife, Elaine Chao, the country's transportation secretary, and the Senate 'wish John the very best and wish him a speedy recovery.'
McConnell said that in McCain's absence the Senate would continue its work on other legislative matters and nominations by President Donald Trump to fill various positions throughout federal agencies.
FILE - Senate Majority Leader Mitch McConnell of Ky., joined by, from left, Sen. John Barrasso, R-Wyo., and Sen. John Thune, R-S.D., meets with reporters July 11, 2017, on Capitol Hill in Washington.
A week ago, McConnell decided to cancel the first two weeks of the Senate's traditional August recess to allow more time for deliberations on the health bill and other issues.
McCain, who is 80, is 'resting comfortably,' according to a statement by an Arizona hospital.
The Mayo Clinic in Phoenix said in a statement that, following a routine physical, McCain had a procedure to remove a five-centimeter blood clot located above his left eye.
"The senator is resting comfortably at home and is in good condition,' the statement read. 'Mayo Clinic doctors report that the surgery went 'very well' and he is in good spirits.'
McCain, a Vietnam veteran and former prisoner of war, was elected to the U.S. Senate in 1986. He was the Republican Party presidential nominee in 2008, losing the election to Obama.