A growing Democratic Party rebellion is rattling the party’s establishment, as a wave of left-wing insurgents topples hand-picked candidates across the country. Party leaders increasingly fear they’re staring down their own version of the Republican Tea Party uprising from nearly two decades ago, and worse, that there may be no way to contain it.

A Party at War With Itself

The recent string of primary victories by Democratic socialists and outsiders has stunned establishment Democrats. Yet the anger fueling these wins didn’t appear overnight. It has been simmering for roughly a decade.

What makes this moment particularly difficult to navigate is that it can’t be reduced to a simple progressives-versus-moderates fight. The deeper divide runs between insiders and outsiders, with a significant share of Democratic voters expressing frustration with their own party’s leadership. Some Democrats now worry the party is ripe for a Trump-style figure to seize control in 2028, someone capable of channeling all that pent-up rage.

Dan Pfeiffer, a former top aide to Barack Obama and now a co-host of “Pod Save America,” summed up the shift bluntly. He observed that left-wing groups like Justice Democrats, the Democratic Socialists of America, and Our Revolution are simply outworking the traditional party machinery, out-organizing, out-fundraising, and out-maneuvering it at nearly every turn.

The Roots of the Revolt

To understand the current upheaval, you have to go back to 2016. The growing distrust among Democratic voters traces directly to Donald Trump’s victory over Hillary Clinton that year, and to how the party handled its own primary.

During that cycle, many voters came to believe the deck had been stacked. Party elites and Democratic National Committee members worked to secure the nomination for Clinton over progressive favorite Bernie Sanders. The tactics raised eyebrows and later fueled lasting resentment:

• Primary debates were limited in number
• Unusual joint fundraising agreements linked the DNC and Clinton’s campaign
• A 2016 WikiLeaks email release confirmed the DNC’s internal bias against Sanders

That sense of a rigged process planted seeds of mistrust that would only grow over the following years.

A Pattern Repeats

The 2016 episode wasn’t an isolated grievance. Many voters saw the same dynamic play out again in 2020, when the Democratic establishment coalesced around Joe Biden specifically to block Sanders, viewing Biden as the more electable option.

Biden went on to win the presidency, though only narrowly, despite Trump’s turbulent handling of the COVID-19 pandemic. His time in office proved largely unpopular and was often criticized as lacking energy. Even so, he embraced a number of left-wing priorities that Sanders and others had long championed, including aggressive antitrust enforcement, massive clean energy investments, and strong backing for labor unions.

Then came 2024. Democratic leaders, critics argue, went along with the questionable belief that the 81-year-old Biden could handle a second term. Trump’s eventual victory that year radicalized a segment of Democratic voters who had once dismissed his first term as a fluke. For many, it shattered whatever remaining trust they had in their party’s leadership and set the stage for the rebellion now unfolding.

Victories From Coast to Coast

Against this backdrop, left-wing and outsider candidates have piled up wins across the country during Trump’s second term. The momentum has been hard to ignore.

The breakthroughs span multiple states and levels of government:

• Following the election of New York City Mayor Zohran Mamdani, progressives unseated two incumbent Democratic House members in the city
• Candidates backed by the Democratic Socialists of America won eight of nine decided races for the New York legislature, several while being outspent
• Democratic socialist Janeese Lewis George captured D.C.’s Democratic primary for mayor by energizing young voters around affordability
• Marine Corps veteran Graham Platner defeated Maine Gov. Janet Mills to claim a Senate nomination that could decide control of the chamber
• In California, Sanders- and Alexandria Ocasio-Cortez-backed Randy Villegas beat the party leadership’s preferred candidate
• AOC-endorsed Chris Rabb won an open House primary in Pennsylvania
• Sam Forstag triumphed in Montana with backing from Sanders and AOC
• First-time candidate Adam Hamawy won a crowded New Jersey House primary, also supported by Sanders and AOC

Lessons From the Tea Party Playbook

Some of these new progressive figures are openly studying how the Republican right reshaped its own party. Chris Rabb pointed to the House Freedom Caucus, the disruptive bloc that emerged from the Tea Party in 2015 and dragged the GOP rightward.

Rabb argued that even a modest but disciplined progressive voting bloc could wield real influence. In his view, the power lies partly in the ability to say no, to refuse to support legislation and force party leaders to try again. That kind of defensive leverage, he suggested, can be surprisingly potent within a narrow majority.

Not Everyone Is Convinced

Despite the headlines, the establishment isn’t in full retreat, and not every party-backed candidate has fallen. Plenty of incumbents have fended off challenges with relative ease.

Rep. Ritchie Torres of New York, for example, comfortably turned back a left-wing primary challenge in his Bronx district even amid his vocal support for Israel. House Democratic leader Hakeem Jeffries downplayed the broader significance of the insurgent wins, suggesting that a handful of primaries breaking one way or another in a state or two won’t fundamentally reshape who House Democrats are.

There’s also disagreement within the left itself about how confrontational to be. Greg Casar, who chairs the Congressional Progressive Caucus, drew a clear distinction between his group and the Tea Party and Freedom Caucus, arguing those earlier movements were in many ways at war with their own party in a way he doesn’t endorse.

What to Watch Next

Democrats are now keeping a close eye on a series of upcoming primaries that could reveal just how deep the anti-establishment sentiment runs. Several contests stand out as key tests.

The races to watch include:

• Multiple primaries in Colorado, including the governor’s contest and a Denver-based congressional seat where a young democratic socialist is challenging a longtime incumbent
• The gubernatorial primary in Wisconsin, where some state Democrats fear democratic socialist Francesca Hong could prevail
• The Senate primary in Michigan, where left-winger Abdul El-Sayed could upset the establishment’s preferred choice

A Defining Struggle

The tension gripping the Democratic Party reflects a genuine reckoning over its identity and direction. Whether the insurgents ultimately reshape the party the way the Tea Party transformed the GOP, or whether the establishment manages to absorb and channel the energy, remains an open question.

What’s clear is that the frustration driving this movement has been building for years and shows little sign of fading. As the 2028 cycle approaches, the battle between insiders and outsiders may well determine not just who leads the party, but what the party stands for in the years ahead.