During the last few election cycles, Democrats have gleefully watched as the Republican Party ripped itself apart in a battle over ideological purity. But they shouldn’t get too comfortable: Their civil war is upon us, too.

In 2010 and 2012, divisive Senate primaries led to unpalatable GOP general-election candidates in Nevada, Delaware, Missouri, Indiana and Colorado — all states that could have elected Republican senators and provided a nearly filibuster-proof majority. Democrats laughed as the GOP shot itself in the foot.

Now, in 2016, I have three words for Democrats: Winter is here. Your party is now locked in a fierce civil war, the populists are at the gate and there are more bloody battles in store.

In one corner is the Hillary Clinton wing of the party, represented by the liberal establishment in the Acela Corridor. These are the left-of-center party leaders interested only in preserving power.

In the other is the Elizabeth Warren/Bernie Sanders wing that rose to prominence on the backs of the radical Occupy Wall Street protest movement. Vehemently opposed to American free enterprise, these extremists are fueled by burning left-wing populism and hostility toward capitalism. They demonize success by pitting the so-called “one percent” versus the “99 percent,” and have less interest in governing than they do advancing ideological purity.

The growing influence of the Warren/Sanders wing of the party is obvious. Despite spending nearly $200 million in the Democratic primary, Clinton has still failed to close out a 74-year-old socialist who doesn’t even comb his hair.

Even though Clinton will eventually stagger to her party’s nomination, the Democratic civil war is far from over.

The headlines have been dominated by a widening schism led by enraged Sanders supporters who believe their candidate has been treated unfairly. The clash has also spilled over into key Senate races. In Florida, for example, an explosive altercation between Senate Minority Leader Harry Reid and progressive flamethrower Alan Grayson grew so heated that Reid’s security detail was forced to intervene.

In Pennsylvania, it took nearly $5 million from the liberal DC establishment to push its candidate for Senate, Katie McGinty, over the finish line against her upstart challengers.

At the top of the ticket, one major point of contention has been the Democrats’ reliance on the undemocratic superdelegates who have greatly benefited Clinton.

In mid-May, the type of violence that marked the Occupy Wall Street movement erupted at the Nevada Democratic Convention with competing factions hurling insults, chairs and even death threats at each other. By mid-week, the Nevada Democratic Party formally filed a complaint charging the Sanders campaign with “fomenting violence.”

In an extraordinary turn of events, Sanders endorsed and even fundraised for the populist primary challenger to DNC Chairwoman Debbie Wasserman Schultz, a controversial figure who co-chaired Clinton’s 2008 presidential bid and has faced accusations of rigging the system for her in 2016.

As the populists take over, the establishment faces a choice: acquiesce or fight for the heart and soul of their party. Clinton’s pick for vice president will provide an indication of which direction she intends to take.

If she names Warren as her running mate, it would be a clear signal the keys have been turned over to the populists. The Occupy Wall Street crowd that began at Zuccotti Park five years ago will now potentially be one heartbeat away from leading the free world.

Even if Warren is passed over, she and her acolytes will have left a permanent mark on Clinton and her party. Under constant pressure, Clinton has lurched leftward on a host of hot-button issues like trade, criminal justice, energy and her views toward the financial services industry. Clinton limps out of the bitter Democratic primary a far different candidate than when she entered last April.

The ultimate victor in this struggle has yet to be determined, but the battle lines have been drawn, there are many political casualties ahead and the future of the Democratic Party hangs in the balance.

Matt Rhoades was the campaign manager for Gov. Mitt Romney’s 2012 presidential campaign, and founded the GOP super PAC America Rising and Definers Public Affairs.