Republicans’ last-ditch effort to repeal the Affordable Care Act before the clock runs out on their ability to do it with a simple majority does not have a CBO score, does not have the enthusiastic support of GOP leadership, and most importantly, does not have 50 votes.

But the same health advocacy groups that mobilized in opposition to Obamacare repeal bills this spring are treating the distant prospect that the bill could come to the floor in the next two weeks as an emergency—blasting out press releases and urging their networks to once again pack GOP town halls and tie up Congress’ phone lines until the bill is dead for good.

With an eye on the Sept. 30 deadline set by the Senate parliamentarian for passing a bill with 50 senators instead of the usual 60, Senate Republicans are furiously whipping votes for the awkwardly named Graham-Cassidy-Heller-Johnson bill, which would repeal many of Obamacare’s taxes, mandates, and subsidies while converting Medicaid and the ACA exchanges into block grants controlled by each individual state. States would be able to use the funding, which would be cut deeply over the next decade, to redesign their health insurance markets, and could also waive Obamacare’s protections for people with pre-existing conditions if they so chose.

Depending on whom you believe on Capitol Hill, the bill has between 45 and 49 votes. Crucially, Sen. John McCain (R-AZ), who dramatically helped to tank the Senate’s last Obamacare repeal effort, is a tentative yes. But conservative groups are messaging against the bill, and several Republican senators remain anywhere from skeptical to openly hostile to the plan.

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

The other two senators who helped to kill the last ACA repeal bill—Lisa Murkowski (R-AK) and Susan Collins (R-ME)—have also shown no interest in supporting the new bill, and have in the past vocally opposed many of its elements, such as setting a per capita cap on Medicaid and defunding Planned Parenthood. Those three GOP lawmakers along are enough to stop the bill in its tracks, even with the lower vote threshold.

Still, leading pro-Obamacare advocacy groups like MoveOn.org, Protect Our Care, Save My Care, and Indivisible are sounding the alarm.

“After Speaker Ryan snuck repeal through the House when everyone thought repeal was dead, we are taking this threat very seriously as urgent and real,” Protect Our Care’s spokesperson Meaghan Smith wrote to TPM.

Indivisible’s policy director Angel Padilla told TPM that even if the GOP’s senators’ trumpeting of the bill’s chances turns out to be “a big headfake,” he wants to make sure he and other activists did all they could to oppose it.

“Earlier this summer, the Senate tried and failed in an embarrassing way. They want to avoid that same embarrassment at all costs. So if they’re pushing it now, that means they’re confident, which makes me really nervous,” he explained. “I know they’re projecting confidence and faking momentum to gain momentum. But we don’t think it’s worth assuming anything. If there’s a real threat here, we have to make sure we meet that threat. We don’t want to make the mistake a lot of people made back in May by thinking this is dead.”

Padilla added that he has become a lot more anxious about the repeal bill’s chances over the past two weeks, following President Donald Trump’s recent budget and debt ceiling agreement with Democratic leaders that cleared much of the month’s calendar.

“Early on in September, we said, ‘Look at how crazy jam-packed this month is. This is going to be a tough month for them to do anything.’ But that deal that Schumer and Pelosi cut made it a lot easier for Republicans to pursue what they really want, including this.”

Even with the debt ceiling, the budget and aid to victims of recent natural disasters taken care of, Congress still has a full plate for the next two weeks. They must finish the National Defense Authorization Act, the Children’s Health Insurance Program’s reauthorization, and they are still hoping to craft an Obamacare stabilization bill by the end of September.

“We are calling on Democrats to withhold consent and slow the process down on the NDAA,” said Padilla. “It is too risky for them to give the NDAA a free pass. We need to slow down everything. The goal here is to run out the clock and undercut the momentum they’re building.”

On Monday, Save My Care went after Sen. Dean Heller (R-NV), one of the most vulnerable Senate Republicans up for reelection next year, in a sizable digital ad campaign, accusing him of breaking his promise to protect people with pre-existing conditions by supporting the new bill.

Indivisible, Protect Our Care, MoveOn.org and the Center for American Progress are also pushing their members and followers to bombard senators’ phone lines with calls in opposition to the bill and show up to their district offices, and are currently developing a plan to hit lawmakers who support the bill and those who remain on the fence with digital and TV ads.

Though many Democrats in Congress have their attention elsewhere, several have said openly that they will remain on high alert until the Sept. 30 deadline for a 50-vote Obamacare repeal has passed.

“It’s time to mobilize again folks,” Sen. Ron Wyden (D-OR) tweeted on Friday. “People power can stop this.”