A number of recent high-profile congressional primaries in the Democratic Party have resulted in the nomination of unexpected candidates. Many of these winning candidates have unseated entrenched incumbents, as 29-year-old Colorado attorney Melat Kiros did to U.S. Rep. Diana DeGette, who has been serving in the House for three decades.

Some of these candidates are explicitly running under the banner of the Democratic Socialists of America, known as the “DSA,” a far-left organization known for standard-bearers such as U.S. Sen. Bernie Sanders of Vermont, and U.S. Rep. Alexandria Ocasio-Cortez of New York. New York City’s charismatic mayor, Zohran Mamdani, won his election as a DSA member in 2025 and has since marshaled political support for fellow progressives running for other offices in the city he runs.

Mamdani loaned his star power to three New York progressives, two of them DSA members, in an ad featuring promises to “abolish ICE” and “end corporate greed.” All three went on win their congressional primaries in June 2026.

There is no doubt that the DSA is having a moment within the Democratic Party. And since their candidates in the midterm races are all but guaranteed to win their safely Democratic districts, I believe their influence is likely to be a major factor on Capitol Hill in the next Congress.

That’s especially the case if the Democrats win the House with a narrow margin. The cooperation and votes of a handful of DSA members could be crucial to Democrats’ ability to act effectively as a majority – or not.

That’s because the DSA’s far-left positions on issues such as healthcare in the form of Medicare for All, defunding the police and taxing the ultrawealthy are likely to divide the Democrats, many of whom are more moderate and/or represent conservative districts.

But as a political scientist who studies the many methods politicians have available to represent their constituents, I’m seeing a story that’s more complex than many inside or outside the Democratic Party convey.

Affiliation with the DSA, or even just a far-left ideology, explains only some of the insurgent wins seen in the primaries. In reality, the Democrats’ reckoning is more complicated.

Who is – and isn’t – a democratic socialist?

Ascertaining the influence of the DSA in the Democratic Party, or in American politics as a whole, means understanding its membership among both elites and its voters.

Sanders, Ocasio-Cortez and Mamdani are all well known, charismatic and proficient fundraisers on the left, as is Rashida Tlaib of Michigan, a second DSA member of the House. And come January 2027, when a new Congress is seated, at least three more – the aforementioned Kiros of Colorado, along with Darializa Avila Chevalier and Claire Valdez, who won primaries in two heavily Democratic seats in New York in June – will almost certainly be added to their ranks. These figures have all won their nomination contests within the Democratic Party but describe themselves as, and received official endorsements from, the DSA.

Meanwhile, the number of voters who officially affiliate as dues-paying members of the DSA is also on the upswing, nearly doubling since Mamdani began his viral mayoral campaign in 2025. Like their candidates, these voters largely participate in Democratic primaries rather than hold their own third-party contests.

But the DSA’s total official membership remains at around 100,000: formidable, but a minuscule percentage of the population compared to the two major parties. And even among this year’s crop of insurgent Democratic candidates, most do not affiliate with the DSA, including a number of ideological progressives.

For example, Graham Platner, the Democrats’ embattled U.S. Senate nominee in Maine, is an economic progressive who boasts an early endorsement from Sanders. But in an interview late last year, Platner declined to be identified as a democratic socialist, saying, “It’s not my politics.”

Brad Lander, New York City’s former comptroller and city councilman who recently won the Democratic primary against incumbent U.S. Rep. Dan Goldman, is also widely recognized as a progressive – and was backed by Mamdani – but does not currently affiliate with the DSA.

Not all insurgent candidates are alike

Even among this cycle’s insurgent progressives, political ideology is not the only differentiating element that seems to matter to Democratic primary voters.

And the democratic socialists’ far-right 2010s counterpart, the tea party, can help shed light on these nonideological factors.

The tea party emerged during Barack Obama’s presidency as a far-right ideological movement with an ostensible focus on fiscal conservatism. And in my own research with Stella Rouse and Kristen Essel, we found that tea party-affiliated state legislators were more ideologically conservative in their voting records.

These legislators were also more likely to be white, to have served in the military and to be religiously observant. Other research has identified the tea party movement driven just as much by Obama-era racial backlash as it was by the movement’s stated fiscal concerns.

Most importantly, we found that tea party-affiliated lawmakers in state legislatures shared a number of anti-establishment tendencies and characteristics. They were less likely to have held previous elected office, to have sought party leadership positions or to have worked with the party before holding office.

Many of these same differentiating elements, such as racial and ethnic identity or a distaste for the established way of conducting politics, are clearly factors among insurgent Democrats this cycle, DSA or not.

Race, age, Israel and Palestine

Many, for example, would add to the ranks of nonwhite members of Congress if elected in November; and nearly all have either questioned or explicitly dismissed the idea of retaining Sen. Chuck Schumer and Rep. Hakeem Jeffries – both New York Democrats – as the party’s congressional leaders.

Age is a related emerging factor in Democratic primaries, which are producing many young nominees.

Kiros, Chevalier and Valdez are 29, 32 and 36, respectively. In the Democratic primary, Platner, 41, beat back Maine’s governor, Janet Mills, who is 78.

And in New York’s 12th District, two comparatively young Democrats, Micah Lasher and Alex Bores, were the top two vote-getters in the race to succeed U.S. Rep. Jerry Nadler, 79, who finally relented to calls for his retirement due to his advanced age. Lasher won the primary and is nearly assured of a win in the heavily Democratic district.

In still other cases, insurgent candidates – DSA or not – have adopted positions on specific issues that mark them as a new generation of Democrats. Most prominent, and controversial, among these is their backlash against Israel, which has propelled an increasing number of pro-Palestine candidates to nomination, often over long-serving incumbents.

For example, the recently defeated Goldman in New York had continued to stake out pro-Israel positions, even as the Democratic Party has increasingly soured on that nation’s actions in Gaza. Goldman’s victorious opponent, Lander, made these positions a relentless focus of his campaign.

What does the DSA mean for Democrats?

It is all but guaranteed that next year’s Congress will feature more democratic socialists than this one. But it is also clear that not all of this cycle’s insurgent Democrats share that label, and that they differ from longer-serving Democrats in more ways than one.

In our research, we found that the tea party was best understood as a “factional group” rather than a separate party, and that its goal was to transform the Republican Party “in ways that go beyond ideology.” Given the U.S.’s entrenched two-party system, this may be the most accurate way to understand the new roster of insurgent Democrats, whether they identify as democratic socialists or not.

Regardless of these candidates’ motivations or DSA affiliations, the Democratic Party will need to reckon with their divergent ways of representing their constituents, particularly if the party retakes one or both chambers of Congress next year. If the factionalism tearing through the current Republican majority is any indication, the Democrats should probably prepare for some new and sharper divisions in their own ranks.

Charlie Hunt does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.