Senate Republicans on Tuesday resuscitated their health care legislation for now, narrowly clearing it past a key hurdle with the help of Sen. John McCain’s dramatic return to the chamber for the first time since his brain cancer diagnosis.

The Senate voted 51-50 to start debate, with Vice President Pence casting the tie-breaker. The procedural vote once again brings the ObamaCare overhaul legislation back from the brink of collapse, after intense pressure from President Trump who had demanded senators skip recess until they act on health care.

The bill still faces a tough road ahead. But it was a heavy lift just to get to this point.

No Democrats supported the motion, leaving Republicans to corral the necessary 50 votes. They got exactly that, requiring Pence to break the tie, for the fifth time under the Trump administration.

The airtight vote made McCain’s return all the more significant, as the measure could not have advanced without him.

The result was kept in suspense for a while. Sens. Susan Collins, of Maine, and Lisa Murkowski, of Alaska, voted no from the start. Several other Republican senators then delayed casting their vote, with no wiggle room left for additional defections on the GOP side.

Applause then broke out as McCain entered the chamber, pointing at his colleagues and shaking hands. As he joined, the last GOP holdout, Sen. Ron Johnson, R-Wis., voted with the Arizona senator to start debate.

Trump applauded the development in a statement, urging the Senate to follow through:

"I applaud the Senate for taking a giant step to end the Obamacare nightmare. As this vote shows, inaction is not an option, and now the legislative process can move forward as intended to produce a bill that lowers costs and increases options for all Americans. The Senate must now pass a bill and get it to my desk so we can finally end the Obamacare disaster once and for all."

Tuesday’s procedural vote kicks off what is likely to be another intense round of debate on health care, in which senators are sure to propose numerous changes to the plan – which could either boost or doom its chances. If a bill passes, it would still have to be reconciled with the House version.

McCain warned colleagues after the test vote that he would not support the bare-bones, “shell” bill in its current form as he urged lawmakers from both parties to reach across the aisle.

“We’re getting nothing done my friends,” McCain said from the floor, adding “something has to be done” on health care.

As the test vote began, Senate Majority Leader Mitch McConnell, R-Ky., urged his Republican colleagues to follow through on campaign promises to repeal and replace the Affordable Care Act.

“We have a duty to act. … The president is ready with his pen,” he said. “We can’t let this moment slip by.”

Moments earlier, Senate Minority Leader Chuck Schumer, D-N.Y., beseeched Republicans to “turn back.”

“We know the ACA is not perfect. But we also know what you’ve proposed is much worse,” he said.

A rowdy group of protesters also interrupted the start of proceedings, chanting, “kill the bill, don’t kill us” and “shame.”

For their part, Democrats uniformly oppose the effort to tear down President Barack Obama's signature legislative achievement. Republicans control the chamber 52-48, meaning they could afford to lose just two Republicans with McCain around.

Trump had kept up the pressure on GOP lawmakers, tweeting that "After 7 years of talking, we will soon see whether or not Republicans are willing to step up to the plate!" He added: "ObamaCare is torturing the American People. The Democrats have fooled the people long enough. Repeal or Repeal & Replace! I have pen in hand."

McConnell's original bill would abolish much of Obama's law, eliminating its tax penalties on people not buying policies, cutting Medicaid, eliminating its tax boosts on medical companies and providing less generous health care subsidies for consumers. But at least a dozen GOP senators have openly said they oppose or criticized the measure, which McConnell revised as he's hunted Republican support.

For the time being, he won over Sen. Rand Paul, R-Ky., who backed starting debate. He said McConnell told him the Senate would debate Paul's proposal to scuttle much of Obama's law and give Congress two years to enact a replacement -- an amendment that seemed certain to lose.

Moderates also were seeking additional money for states that would be hurt by cuts in Medicaid, the health insurance program for the poor, the disabled and nursing home patients. Conservatives wanted a vote on a proposal by Ted Cruz, R-Texas, letting insurers offer bare-bones policies with low premiums, which would be illegal under Obama's law.

With leaders still struggling to line up enough votes to approve a wide-ranging overhaul of Obama's law, there was talk of trying to pass a narrow bill -- details still unclear -- so House-Senate bargainers could craft a compromise.

The Associated Press contributed to this report.