Tresa Undem, a pollster who specializes in surveys on gender issues, said that discussions of fairness and power carry more political currency than they used to just a few years ago. Voters have started using terms like misogyny and patriarchy in focus groups — words Ms. Undem never heard mentioned until Donald Trump won the White House.

Even so, she notes, Ms. Gillibrand’s message was not enough to distinguish her beyond the audience of the activists, strategists and political junkies covering every twist of the primary race.

“We all see her as the woman candidate but she’s not really because they’re all talking about these issues,” Ms. Undem said. “Just take abortion; every single candidate is against the Hyde amendment.”

Some of the explanation for how her campaign unfolded clearly rests with Ms. Gillibrand, who struggled to connect with a broad enough range of voters.