In Macomb County, Mich. — the well-chronicled home of the Reagan Democrats and a county Mr. Trump decisively won — about 6,000 Democrats braved frigid temperatures on Jan. 15 to hear Mr. Sanders and Senator Chuck Schumer of New York, among others, defend the Affordable Care Act. It was one of dozens of similar rallies across the country.

The day before, so many constituents of Representative Mike Coffman, Republican of Colorado, packed an Aurora library to confront him over his support for repealing the health care law that he had to leave through a back door.

Yet it was telling that women galvanized the largest protests. Hillary Clinton’s defeat prompted soul-searching about why appeals to feminism did not carry the day. Now a wide range of groups that advocate for women are trying to capitalize on the momentum to turn an event into a sustained movement.

Todd Gitlin, a former president of Students for a Democratic Society and a scholar of political movements, noted that the civil rights and antiwar movements succeeded because of the organized networks that preceded and followed any single mass protest. “The march on Washington in 1963 was the culmination of years of local activism, including civil disobedience, registering voters, protecting civil rights workers and voter education movements,” he said. “Organizations need to be ready to receive the protesters when they’re ready to take the next step. You need to be a full-service movement.”

That effort, the organizers say, is already underway. At the panel Saturday night, representatives from the partner groups made 90-second pitches to the marchers, urging them to sign up for any of the organizations that appealed to them. The key, Ms. Poo said, was to build a continuous relationship with voters and volunteers so that they are not only approached before elections.

Tresa Undem, a partner in the polling firm PerryUndem, said that several years of convening focus groups had convinced her that women’s issues can translate into political momentum. When she showed focus groups a list of specific restrictions on abortion and health care that had been passed on the local level, she said, they immediately began talking about how men were making those decisions. A poll she conducted that was released this month found that outrage at Mr. Trump’s remarks was the primary predictor of whether women would take specific political actions.

Still, the women’s movement faces several potential obstacles.

Leaders believe the only way to mobilize is to sweep in many disparate groups, which risks diluting their message. And the wounds inflicted by the election still run deep. Minority women in particular say they are concerned that the new attention to the white working class might mean de-emphasizing issues of race for fear of alienating white voters.