Ayanna Pressley’s victory is the biggest win yet for progressives.

Momentum is a tricky thing, though, and the story of whatever is happening on the left flank of the Democratic Party is more complex than most grand narratives admit. Alexandria Ocasio-Cortez, a progressive organizer and former bartender, kicked the narrative machine into overdrive with her shocking win over New York Congressman Joe Crowley in a June primary. Many diviners back then saw her as the bleeding edge of the progressive political revolution that Senator Bernie Sanders had once promised. Since then, two popular narratives have emerged: Candidates from marginalized groups are having a banner year across the country, and progressives are pressing an advantage against the establishment. Incumbents beware.

Reality—with its lessons now applicable as voters head to the polls in Delaware—has adjusted those narratives. Yes, candidates such as Ocasio-Cortez, Pressley, Andrew Gillum in the Florida gubernatorial election, and Stacey Abrams in the Georgia governor’s race are part of perhaps the most diverse class of liberal candidates since Reconstruction, and one that skews younger and more unabashedly progressive than before. But, for the most part, they still exist at the outer limits of power and prominence. Several members of this group of enfants terribles failed to break through the establishment strength and fund-raising capabilities of the Democratic machine in the Midwest. Those in competitive states or districts—for whom the November election won’t be a formality—still face serious challenges from the GOP.

Even with Pressley’s win on Tuesday, it’s still unclear how translatable individual shockers are to larger movements or other candidates. One main advantage for contenders such as Ocasio-Cortez and Pressley appears to be a thicker-than-usual fog of war, which is genuinely interfering with incumbent candidates’ ability to assess risks and moods on the ground. But that lack of acuity also makes it impossible to predict whether a candidate such as Harris—a gay, biracial Air Force veteran who blends a working-class appeal with a staunchly progressive platform—really has a chance against a Carper, a leader in a local machine as formidable as any.

For her part, Harris acknowledged when we spoke that hers was an uphill battle. “It’s looking like we could have a win, but even if we didn’t, we have created a win here in the state of Delaware because people are energized and motivated,” she told me. “We’ve brought back the idea that primaries do matter, and that it’s important to actually look at the record of our elected officials we’ve had here in our state.”

Harris has positioned her platform as far in opposition to Carper’s as two members of the same party can really get. Earlier this year, Carper was one of the Senate Democrats who crossed over and voted in favor of a partial repeal of Dodd-Frank bank reforms that proponents say protected consumers. Harris has criticized Carper for formerly supporting the Keystone XL pipeline and other major oil projects, although he has walked back some of his previous support. And Carper has firmly resisted the leftward gravitation toward ideas such as “Medicare for all” and student-debt forgiveness.