WASHINGTON – The slim Senate margin to debate and decide the fate of the nation’s health care system succeeded on the votes of two Republican moderates going along with their party leaders to get along.

Sens. Shelley Moore Capito of West Virginia and Rob Portman of Ohio indicated in advance they had misgivings about starting the Senate’s sausage-making process without an acceptable bill to protect Medicaid funding.

But a last-day push by President Donald Trump and Senate Majority Leader Mitch McConnell convinced both lawmakers to fall in line and hope for the best during the free-wheeling floor debate to either repeal and replace the 2010 Affordable Care Act, modify it or dump it.

The Capito and Portman votes were critical to the 51-50 vote that carried the day for the Republicans and set the stage for contentious judgment on the law commonly known as Obamacare.

Vice President Mike Pence cast the tie-break when two other moderate Republicans – Sens. Susan Collins of Maine and Lisa Murkowski of Alaska – voted against their party’s wishes and with the 48 objecting Senate Democrats.

Republican Sen. John McCain, recovering from blood clot surgery and a diagnosis of brain cancer, dramatically returned from Arizona to vote for charging ahead even though he said he could not support the repeal and replace bill offered by the House. He urged lawmakers to come up with a bipartisan health care plan.

Still, the spotlight was clearly on Capito. She tweeted a week ago she would not support a go-for-broke approach “without a replacement plan that addresses my concerns” about devastating cuts to Medicaid funding for her West Virginia, a state with a greater share of its population covered by the program than any other.

She said in a statement shortly before casting her vote that she remains “committed to reforming our health care system while also addressing the concerns I have voiced for months,” including protecting insurance coverage for “those who are in the Medicaid population and those struggling with drug addiction.”

Trump flew to West Virginia Monday to speak at the National Boy Scout Jamboree, using the occasion to also disparage Obamacare and cajole Capito into supporting the Senate effort to get rid of it.

McConnell told Capito, Portman and other holdouts they will have an opportunity to offer amendments on Medicaid and other issues during the Senate debate. He made no mention of working with Democrats on a compromise.

Sen. John Cornyn, R-Tex., the Senate whip in charge of keeping Republicans in line, predicted the debate over what to do about Obamacare and how to fix it would go “into the wee hours.”

McConnell did float the idea of a limited repeal bill that would eliminate Obamacare’s mandatory insurance provisions and the tax on medical devices. This was dubbed “skinny repeal.”

McConnell also said the Senate would take up Texas Sen. Ted Cruz’s proposal to allow health insurers to sell bare-bones plans that do not include basic coverage such as prescription drugs, maternity care and mental health services.

Senators will also vote on a proposal by Portman to give states $100 billion to make up for a portion of eliminating all funding that allows them to expand Medicaid to lower-income individuals who can’t afford insurance.

Tuesday’s razor-thin vote was a victory for McConnell in that it did not appear a few days ago he had sufficient votes to open debate on Republican plans to repeal and replace Obamacare.

He reminded Republicans before the vote that “the president is ready with his pen. The House has passed legislation already. Today, it’s the Senate’s turn.”

Contact Washington reporter Kery Murakami at kmurakami@cnhi.com.