The Obamacare repeal drama is back, and everybody is picking up where they left off.

Senate Republicans are trying to build momentum for a last-gasp bill to replace the Affordable Care Act, swearing that they are once again just a few votes short of delivering on their seven-year pledge. The health law’s supporters are trying to regalvanize the base that helped beat back previous repeal attempts, worried about being caught off-guard by a new plan that nobody took seriously until recently.

An imminent deadline is fueling the sense of urgency: Republicans have until the end of the month to act on a repeal bill. Otherwise, they’d need to start the process over at the very beginning — by passing a new budget resolution — or win Democratic support for it. Neither is particularly appealing, so this could very well be the GOP’s last shot for the foreseeable future.

But what isn’t clear — and really all that matters — is whether the underlying math has swung in the GOP’s favor. It’s easy for Republicans to get 40-plus votes for Obamacare repeal. But bridging the gap to a majority of 50 has so far proven impossible.

Two Republicans, Sens. Lisa Murkowski (R-AK) and Susan Collins (R-ME), have opposed every version of repeal so far, and a third, Sen. Rand Paul (R-KY), has said he opposes the latest plan. That trio would be enough to stop it on their own.

For now, the authors of the last-ditch repeal-and-replace bill, Sens. Lindsey Graham (R-SC) and Bill Cassidy (R-LA), are talking a good game. Cassidy told reporters Friday that he thought their bill, which would turn much of Obamacare’s funding into block grant sent down to the states with few strings attached, had 48 or 49 Senate Republicans behind it.

“I am pretty confident that we’re gonna get there on the Republican side,” Cassidy said. Graham laid out a similar whip count to reporters on Thursday.

That leaves them just shy of the 50 votes they need to repeal the health care law.

But you can look at the math a very different way: Senate Republicans will always be a handful of votes away from repealing Obamacare. That’s the whole problem. Their original version of repeal-and-replace got 43 votes. A cleaner repeal bill got 45. Their last-ditch plan in late July, a very narrow repeal plan, got 49.

So they are perennially right on the edge without ever getting over it. Cassidy-Graham has yet to prove it can break through: While Sen. John McCain (R-AZ), whose dramatic vote against so-called “skinny” repeal killed the crusade in July, has spoken positively about the bill, Paul stated in no uncertain terms Friday morning that he would oppose it.

I can't support a bill that keeps 90% of Obamacare in place. #GrahamCassidy is not repeal or replace, it is more Obamacare Lite — Senator Rand Paul (@RandPaul) September 15, 2017

Without Paul, Cassidy and Graham would need either Murkowski or Collins to come around and back their bill. After defying their party on several tough votes and earning plaudits from their constituents for their independence, one of those two senators would have to decide Cassidy-Graham is the repeal plan to finally support.

That helps explain why many seasoned observers in Washington are skeptical, especially once you add in the tight timeline. The bill was introduced this week and must be scored by the Congressional Budget Office, analyzed by the parliamentarian, litigated within the GOP conference, and put on the floor — all in less than three weeks.

“I don't see the votes materializing,” one health care lobbyist told me Thursday, even as Senate leaders began to formally take their conference’s temperature.

“They have to go through the motions,” the lobbyist added. “Sort of like when the Senate votes down something ridiculous the House sends them — in order to prove to the crazies don't have the votes.”

It’s hard to separate the Cassidy-Graham fact from fiction

The hype has Obamacare supporters nervous, especially after Cassidy-Graham was dismissed as a pipe dream for the past six weeks. The law’s future seemed secure once the Senate failed to pass three different versions of repeal in late July, but Senate Majority Leader Mitch McConnell has always left the door cracked open for taking another shot if the votes materialized.

Protect Our Care, the leading pro-Obamacare group that has fought the GOP’s repeal efforts, blasted out an email memo on Friday warning that the “Graham-Cassidy Threat Is Real.”

But the question is: Are the votes actually materializing?

Much of the forward momentum is coming from the handful of senators who are trying to build support for their own bill. Senate leaders have yet to outwardly embrace it, though Cassidy and Graham have said they are supportive. The White House’s public response has been tepid.

The bill could face some unique political challenges. In addition to the likely coverage losses that will be projected and its overhaul of Medicaid, which helped kill previous repeal bills, Cassidy-Graham will have clear state-by-state winners and losers in a way that other bills did not. This is because its block-grant formula redistributes the Obamacare funding from states that expanded Medicaid to states that did not.

Outside estimates from the left-leaning Center for Budget Policy and Priorities have shown states like Alaska, Arizona, Colorado, Kentucky, Ohio, and West Virginia — all states with GOP senators who might be swing votes on the bill — losing hundreds of millions, or even billions, of dollars in federal funding over 10 years.

Cassidy is working with his own numbers, and he will tell you that other provisions in the bill, particularly one that lets states draw down on Medicaid payments to hospitals, will help offset the losses for states under the block-grant formula. He told reporters Friday, for example, that West Virginia would be made whole despite his own projected funding cuts for the state under the block grant.

But he has to make that case to the senators who represent those states, who are likely to hear contradictory analysis from outside experts as well as the CBO. It’s not yet clear whether he’s making progress.

“I’m trying to get the numbers for West Virginia,” Sen. Shelley Moore Capito (R-WV) told me Thursday, though she added: “I think the flexibility piece is something that’s very attractive.”

The Cassidy-Graham plan was discussed at the Senate GOP’s lunch on Thursday, and Cassidy said it “may have been my best day as a senator” after the positive reception he sensed in the room.

Others were a little more reserved, if still positive.

“I think there’s optimism, but nobody really knows what that means,” Capito said. “Is that 30? 40? Who knows.”

So the bill, the last hope Republicans have to repeal and replace Obamacare for the foreseeable future, exists in this strange limbo. It could very well be within a few votes of a majority. At the same time, there is no indication yet it can succeed where other plans have failed and actually secure that 50th vote.

Its authors are naturally hyping the bill’s chances. Leadership is mum. Lobbyists haven’t taken the plan too seriously — too little time and too divisive a plan once you unpack it, they say — though that may be changing.

“While we easily dismissed it for a while, it is becoming something that can no longer be ignored,” one source at a major health care trade group told me Friday. “We are still watching from the sidelines, but watching a lot more closely.”

The uncertainty promises a somewhat manic final two weeks of September. Congress has already cleared the most pressing matters — funding the government and raising the debt ceiling — from its plate. There might not be much else to debate except for Obamacare repeal. The looming deadline could put a fire under Republicans.

That is what has the law’s supporters on edge. They’ve seen repeal come back from the dead too many times to be confident that it will stay dead — at least until it hits the September 30 deadline.