The Democratic Party’s upcoming campaign to save Obamacare will kick off Monday night with a pep rally on the Senate floor.

In an event they say could stretch long into the night, congressional Democrats will live-stream a “talkathon” within the halls of Congress recounting stories from tens of millions of people who stand to lose health care if the Affordable Care Act is dismantled.

Part of the purpose of the event is to steel Democrats for what’s shaping up to be a months-long fight with the new Republican Congress over the law.

“We cannot allow Republicans to make America sick again by repealing the ACA without a replacement plan,” said Senate Minority Leader Chuck Schumer, who is trying to rally his caucus behind the law, in a statement. “Democrats will be fighting tooth and nail against this potentially catastrophic move.”

Of course, on their own, Democrats are powerless to stop Obamacare repeal, which can be jammed through Congress’s reconciliation process with 51 Republican votes.

But as several House and Senate Democratic aides told me last month, the party hopes to use two tried-and-true strategies to combat Donald Trump and the new GOP majority: the outside game — getting the public so riled up that Washington is forced to listen — and the inside game, of lobbying Republicans on Capitol Hill and trying to win over fence-sitting moderates.

How the politics of Obamacare was turned on its head

Since the Affordable Care Act was enacted seven years ago, there was hardly a more unifying message for Republican politicians than the idea that Obamacare was bad and should be repealed.

Now the tables have turned: As Republicans have increasingly splintered over how to dismantle Obamacare, the Democratic Party has largely unified around protecting it.

That development is not entirely surprising. “Opposition to new proposals is a good way to unite a party,” says Matt Grossmann, a political scientist at Michigan State University. “Everyone can be against a new proposal, and they don’t have to agree on a reason why.”

Democrats have also suddenly coalesced around a program they struggled mightily to pass, in part because government programs are always much easier to defend than they are to create, according to Grossmann.

Back when Obamacare was first being debated, there was no organized constituency with a stake in what was still just a promise. But now that the ACA has millions of people who rely on it, it’s far easier for both the public and lawmakers to see who benefits from it. Already, even Blue Dog Democrats like West Virginia Sen. Joe Manchin are pointing to the people in their states will lose health insurance if the law is thrown off the books, Grossmann notes.

“People tend to value losses more than gains — including lawmakers and public beneficiaries,” Grossmann says. “Once you have people benefiting from a law, the dynamics change.”

Of course, whether the uproar will be enough to alter the course of the ACA will depend on the new Trump White House and congressional Republicans. But it’s certainly not impossible. David Gergen, a former White House adviser to two presidents, told me last month what it takes for a concentrated uproar to get an administration to rescind a Cabinet nomination:

It takes an organized outcry, and right now there are a lot of people who are getting aroused or negative about what Trump people are up to. But it's still inchoate — the opposition, it hasn’t really formed. You’ll need a specific issue, something that hasn’t been talked about yet — policy X or decision Y or past thing Z — to just take off and set off a firestorm. The talk shows and social media and op-eds — that's where the boiling starts. But it takes more than that to get things to erupt. It takes either people in the streets or polls that are really wildly lopsided or phone calls from unexpected sources.

Democrats are hoping for a similar story over Obamacare repeal. If their ability to derail George Bush’s Social Security privatization scheme in the mid-2000s is any blueprint, they may have a winning strategy — one we’ll get a glimpse of tonight.