Kara Eastman, the Democratic nominee in Nebraska's 2nd Congressional District

In Tuesday’s biggest upset, nonprofit head Kara Eastman, who also serves as a member of the Metropolitan Community College Board, defeated former Rep. Brad Ashford 51.4-48.6 in the Democratic primary for Nebraska’s 2nd Congressional District. Eastman will take on freshman Republican Rep. Don Bacon in this Omaha-based seat that narrowed from a 53-46 victory for Mitt Romney in 2012 to a much tighter 48-46 win for Donald Trump in 2016.

Eastman's win was a surprise for quite a few reasons. She faced a large financial disadvantage against Ashford, who’d outraised her $559,000 to $356,000 through late April. Eastman did have some support from local Democratic elected officials as well as a few unions, but she didn't have the name recognition of Ashford, a longtime Omaha politician who represented this seat for one term. Ashford also had the advantage of getting placed on the DCCC's Red to Blue list for top candidates, as ex-members seeking comebacks often are, and that may have kept national donors and groups away from his opponent.

While the primary was largely civil (the two candidates’ families are close), Eastman did run against Ashford, a former Republican who has always portrayed himself as a moderate, from the left. Most notably, Eastman emphasized her support for “Medicare for all” and ran a TV ad telling the audience she was tired of hearing that Democrats don't stand for anything. Eastman also likely benefited from running at a time when women have been doing well in Democratic primaries.

Long before the primary was decided, most prognosticators concluded that Eastman would be a weaker nominee that Ashford. Observers argued that the GOP would be able to portray Eastman as too liberal for Omaha, a problem that the more moderate Ashford would in theory be able to avoid. However, despite the conventional wisdom, it's far from clear that Ashford was actually the better bet.