Interviewed over the weekend on Fox News’s Special Report, House Speaker Paul Ryan hinted that the Republican Party’s longstanding promise to “repeal and replace” Obamacare will be fused with his own enduring goal of privatizing Medicare and replacing it with a cash subsidy that almost certainly won’t be adequate to cover senior health care costs. Ryan’s appearance was a preview of the horrors we can expect from the newly emboldened GOP-controlled Congress, which is going to put pressure on Donald Trump to sign a raft of conservative legislative priorities.

But it should also offer Democrats hope in a bleak political era: Privatizing Medicare would be a hugely unpopular move that could tear Trump’s political coalition apart. Launching a pre-emptive attack on the Ryan Plan, especially if done with maximum political theater, offers Democrats a chance to win an early victory against the Republicans. More crucially, it could mark the beginning of a long campaign of divide-and-conquer.

In political terms, the Republicans hold all the cards. They will soon have the presidency, Congress, and (if Trump pushes through his replacement for Antonin Scalia) the Supreme Court. But formal Republican political power masks the fact that the winning coalition Trump has created is highly unstable and will be sorely tested as soon as Trump and the Republican Congress begin to make some political choices.

Consider the figures who are now in power around Trump: Mike Pence, who is a social conservative who believes in gay conversion therapy; Peter Thiel, who is gay and a social libertarian; Stephen Bannon, who wants to launch an alt-right revolution against the GOP elite; and Reince Priebus, a Republican functionary who is the perfect embodiment of that elite. Then there is Trump himself, who has adopted populist policies including expanding infrastructure spending and preserving entitlements, and Paul Ryan, who is an extreme advocate of fiscal conservatism and privatization.

The political task for Democrats going into the next election is to create wedge issues to splinter this coalition. In the 2016 cycle, Trump was able to hold the coalition together by talking out of both sides of his mouth (often incoherently), so different factions thought he represented their interest. Going forward, there will be chances to play the different factions against each other.

There is no more promising division than that between Trump’s economic populism and the deep-seated free-market ideology of Ryan’s faction of the GOP. Trump and Hillary Clinton both campaigned on promises to preserve Medicare and Social Security. This was a key issue that Trump used to differentiate himself from other Republicans (including some who are now his key advisers). As Trump said on MSNBC’s Morning Joe: “Abolishing Medicare, I don’t think you’ll get away with that one. It’s actually a program that’s worked. It’s a program that some people love, actually.”

As Ryan Cooper noted today in The Week, Trump is at odds with Ryan’s radical austerity plan:

He wants to create the perception of a funding crisis to justify cuts. The “Better Way” paper on health care the GOP released in June gives a vision of what they might do — from repealing the ObamaCare cost controls, to expanding the quasi-private Medicare Advantage plans, to destroying Medicare as a public program and replacing it with “premium supports.” With a once-in-a-generation chance at tearing up the Great Society, Ryan is likely going to try to shoot for the moon and go for premium supports.

It can’t be emphasized enough that what Ryan is proposing is political poison, and will particularly hurt working-class voters—a crucial fact given that Trump’s victory relied so heavily on consolidating the white segment of the working class.

Here’s what Democrats need to do immediately: organize an emergency committee to defend Medicare. This committee should be headed by the populist wing of the party: Bernie Sanders, Elizabeth Warren, and Keith Ellison. Other members should include Sherrod Brown, Tammy Baldwin, Catherine Cortez Masto, and Kamala Harris.

The purpose of the committee should be to pick a fight with Trump and Ryan over this issue. The argument should be addressed to working-class Americans, but particularly the former Obama voters who went for Trump in the Rust Belt. The committee should mobilize all over America, with a subsidiary goal of rebuilding the Democratic Party as a force that can win in Congress. This means every state and district should have local committees that are tasked with organizing marches to protect Medicare and to phone local congresspeople (especially Republicans) to reject Ryan’s plan. The Democrats already in Congress should sign a pledge never to privatize Medicare.

It’s essential to hang Ryan around the neck of Trump, to make Trump feel the political cost of going along with Ryan’s agenda. This should be a part of a larger message designed to challenge Trump’s populist pretenses, pointing out all the policies he supports that go against the interest of the working class or enrich the wealthy.

Ryan’s attempt to link the fate of Obamacare with Medicare privatization is a political godsend for Democrats. It means they can frame the defense of Obama’s signature program within the wider preservation of popular policies.

Objecting to this strategy, Ross Douthat of The New York Times tweeted, “The only danger with that fight is that you could end up defeating Ryan but not Trump. Leaving the GOP still more fully in Bannon’s grasp.” The worry about Bannon’s growing power is real, but Democrats can divide Republicans from Bannon on other issues. There are many elements of the Republican Party, notably the foreign policy wing, that will be uncomfortable with Bannon’s foreign policy agenda of creating an alt-right international movement with groups like France’s National Front, the U.K. Independence Party (UKIP), Alternative for Germany (AfD), and the Dutch Party for Freedom (PVV). It’s unlikely that this goal has much favor with traditional Republicans.

There’s an old saying from the Civil Rights Movement: “The people need victories.” Demoralized as they are, the Democrats need victories. The defense of Medicare can give them a fight they can win—one that can help revitalize the party.