The last-ditch Senate attempt to repeal Obamacare with a two-year delay to replace the law appears doomed, just 14 hours after Senate Majority Leader Mitch McConnell proposed it.

Three Republican senators said Tuesday they would not vote to start debate for a repeal plan that does not include any replacement provisions. That is enough to block the bill from moving forward.

It was the only option left to McConnell, after four Senate Republicans came out against the repeal-and-replace plan that McConnell had been carefully crafting for two months. He abruptly dropped that bill and moved to force a vote on the 2015 partial repeal bill that congressional Republicans passed and President Obama vetoed.

Senate Republican leaders — and conservatives like Sen. Mike Lee (R-UT), who were angry the existing Senate bill didn’t roll back more of the law — were betting that any wavering Republicans would feel overwhelming partisan pressure to back the bill.

“A majority of the Senate voted to pass the same repeal legislation,” McConnell said on the Senate floor Tuesday morning. “President Obama vetoed it then. President Trump will sign it now.”

But almost as quickly as McConnell charted that new course, he lost the support to follow through with it. Sens. Susan Colins (R-ME), Shelley Moore Capito (R-WV) and Lisa Murkowski (R-AK) have said they would oppose a procedural motion that would set up a vote on repeal-without-replacement legislation.

“If we’re going to do repeal, there has to be replacement,” Murkowski told reporters. “There’s enough chaos and uncertainty already, and this would just contribute to it.”

Republicans are abandoning Senate leadership’s partial Obamacare repeal plan

Sen. John McCain (R-AZ) is recovering from a health scare in Arizona for at least one week, meaning McConnell can only lose one more Republican senator if he wants to hold the vote before McCain returns.

But the partial repeal bill is estimated to have even more devastating consequences than the Better Care Reconciliation Act: 32 million fewer people with health insurance, compared to Obamacare, according to the Congressional Budget Office. The bill would repeal the law’s financial assistance for private coverage, its Medicaid expansion, its taxes on the wealthy and health care industry, and its individual mandate. It would not repeal the law’s insurance regulations, which are untouchable under the Senate rules, but it could throw the individual insurance market into chaos.

Republican senators might have passed the bill two years ago, when they knew Obama would veto it. But they weren’t ready to do it again while playing with live bullets.

Sen. Susan Collins (R-ME), the only Republican to oppose the 2015 bill, reaffirmed that she would vote to block it from moving forward.

Sen Collins confirms to @kasie that she's still a NO the motion to proceed to the health care bill. — Frank Thorp V (@frankthorp) July 18, 2017

Sen. Shelley Moore Capito (R-WV), one of the senators focused on Medicaid who was hesitant to embrace BCRA over its cuts to that program, also said that she could not vote for a repeal bill that included no replacement plan.

“I did not come to Washington to hurt people. For months, I have expressed reservations about the direction of the bill to repeal and replace Obamacare,” she said in a statement. “I cannot vote to repeal Obamacare without a replacement plan that addresses my concerns and the needs of West Virginians.”

Murkowski then told reporters early Tuesday afternoon that she would oppose the procedural vote to start

Collins, Capito and Murkowski — not even counting the absent McCain — are enough to kill the repeal bill for the foreseeable future.

And it could still lose more support. Sen. Rob Portman (R-OH), who has allied himself with Capito over the Medicaid cuts, also sounded skeptical about voting for the 2015 bill.

GOP Sen. Rob Portman: “If it is a bill that simply repeals, I believe that will add to more uncertainty” and higher premiums. (via @kasie) pic.twitter.com/BKVuIaTGxW — Bradd Jaffy (@BraddJaffy) July 18, 2017

McConnell might hold the partial repeal vote anyway

Unless Senate leaders can steer those wayward Republicans back onboard with a partial Obamacare repeal — with the promise that they’ll figure out a new replacement in the next two years — this new plan appears to be dead on arrival.

Nonetheless, McConnell might decide to hold a vote on it, either to squeeze the holdouts or to put the whole saga six feet under.

“Well, they all did vote for it, when it didn’t matter,” one Republican health care lobbyist told me Monday night. “Basically calling the bluff of his entire conference.”

Conservatives are hankering for a cleaner repeal bill. The repeal-and-delay strategy was discussed earlier this year but ultimately scrapped because it did not have the necessary support to actually pass. But now that the Senate’s own health care plan has gone down in flames, McConnell might hold a vote on partial repeal, giving conservatives a chance to support it and bringing the Obamacare repeal crusade to a more definitive conclusion.

Another Republican lobbyist described it as the “show them a body” strategy to me a few weeks ago: Better to have an irrefutable end to the issue than leave it open-ended and risk conservative and White House pressure to keep working on health care.

It comes with plenty of risks. The moderates who vote against the repeal bill could become the targets of conservative backlash, as Sen. Dean Heller (R-NV) was when he opposed an earlier version of the Senate bill. The GOP base could be demoralized that their party couldn’t achieve what they had promised for seven years to do.

But six months of raucous debate has brought Republicans no closer to an actual plan that can win sufficient support. There may be no other course.