After seven years of bold promises to repeal and replace Obamacare, Senate Republicans failed in the wee hours of Friday morning to approve a "skinny" bill to modify just a few parts of the law.

The major defeat leaves Senate Majority Leader Mitch McConnell, R-Ky., with no clear path to even altering a law he once promised to undo "root and branch." After voting down a repeal and replace proposal earlier this week, and then a "clean" repeal of Obamacare, Republicans couldn't even muster the votes for a fallback bill that would have made just a few changes and was mainly seen as a vehicle to get the bill into a conference with the House.

Ahead of a dramatic vote that was in doubt until the final minutes, Vice President Mike Pence was seen working Sen. John McCain, R-Ariz., in the Senate chamber. McCain flew into Washington this week from Arizona, where he was resting after a diagnosis with brain cancer, to participate in healthcare votes -- and he ended up being a deciding vote against the bill. He joined Republican Sens. Lisa Murkowski of Alaska and Susan Collins of Maine, as well as 48 Democrats, with the bill failing 51 to 49.

A disappointed McConnell thanked members of the Senate for their efforts to reach a compromise, but said, "I regret that our efforts were simply not enough at this time."

He declared, "It's time to move on."

The bill would have repealed the law's individual mandate and temporarily scaled back the employer mandate and the medical device tax. It also would have defunded Planned Parenthood for one year.

"Passing this legislation will allow us to work with our colleagues in the House to work for a final bill to repeal Obamacare," McConnell said after introducing the bill.

But some senators were skeptical about whether the House would actually hold a conference and not just pass the "skinny" repeal bill, which many senators believe was insufficient.

While House Speaker Paul Ryan was able to sway some holdouts by promising to hold a conference, Ryan didn't specifically say that the House would not pass the skinny repeal bill. He was unable to sway McCain.

"The Speaker's statement that the House would be 'willing' to go to conference does not ease my concern that this shell of a bill could be taken up and passed at any time," McCain said in a statement explaining his vote, saying he still believes Obamacare should be repealed and replaced and that he supports starting over at the committee level.

The defeat is a sharp rebuke to McConnell, whose reputation as a master tactician has been put seriously in doubt. He has been criticized by some Republicans for crafting a replacement bill behind closed doors, setting artificial deadlines, and rushing an unfinished product to the floor.

Several Republicans, in addition to McCain, have called for a return to regular order, which involves committee hearings and working with Democrats on a solution to Obamacare's individual market, which has been bereft with rising premiums and insurer defections. But McConnell, in his initial remarks, signaled no plans to continue the repeal and replace effort.

Senate Minority Leader Chuck Schumer, D-N.Y., implored fellow senators to "turn the page." He broke into tears as he spoke about McCain, echoing his calls for regular order.

"We are not celebrating," he said of Democrats' feelings on the vote's failure. "We are relieved."

Congress will still need to make changes to the law to stabilize the exchanges, whether by injecting more funding into the law or by suspending some of its taxes.

Some administrative changes are likely as well, Health and Human Services Secretary Tom Price signalled.

"Since day one of the Trump Administration, the team at HHS has taken numerous steps to provide relief to Americans who are reeling from the status quo, and this effort will continue," he said.