Protesters take part in the Women’s March on Washington on Saturday. (Amanda Voisard for The Washington Post)

The weather was dreary, but the mood was ebullient. Hundreds of thousands flooded downtown Washington with posters, face paint, signs and hats, far more attendees than the organizers had expected. “We’re just so excited to be here,” one woman gushed. “It feels like part of history.”

I’m describing, of course, Saturday’s Women’s March on Washington, not Friday’s inauguration of President Trump. The latter was a much grimmer affair, dogged by protests during the oath of office and the “American carnage” invoked in Trump’s inaugural speech, while the march seemed positively gleeful.

The question, though, is what comes next. Is protest enough? Will the pink “pussyhats” just go to the back of the closet? And what about those women who felt left out from the beginning? Perhaps surprisingly, this march inspires more hope than cynicism.

For many, Trump’s election was followed first by a brief period of shock and then by reaction. Among millennials, in particular, the days after Nov. 8 saw an explosion of shared resources, especially online, about how to engage in the political process in a way they hadn’t before. Whether news articles about effective resistance, documents about how to get involved in local politics, or action-item Facebook posts about which member of Congress to contact, young people finally seemed interested in taking the advice they’d been given by President Obama. (“Don’t boo. Vote!” And if that doesn’t work, do something.) It’s in that spirit that the march was conceived. It may be the energy that keeps its priorities alight.

Saturday’s march attendees seemed to grasp the fact that just protesting wouldn’t be enough, and that the event should be a first step toward something larger. “Today we march, tomorrow we run for office,” read one sign. “A demonstration without follow-up is just … Occupy Wall Street,” said Nancy Xiao, a college senior who had driven from New Jersey to take part. “We feel a different sense of urgency. Instead of saying, ‘Oh, I have to get this and that experience first,’ friends of mine are thinking of running for office now.” Others spoke of networking with like-minded groups, hopefully to form connections that might take root at home.

And despite the divisions that marred the march’s organization — about the involvement of women of color, the exclusion of antiabortion feminists, the perceived co-opting of the march by groups that were perhaps too white, too middle class or too mainstream — a sense of unity seemed to hang in the air. “Of course there’s some disagreement. It wasn’t organized by professionals,“ said Deborah Plummer, vice chancellor for diversity and inclusion at the University of Massachusetts Medical School, who traveled to Washington to meet up and march with a group of black female friends. “But it’s going to be disruptive from now on. If this election said anything, it was that anyone could be president. It’s not who we wanted this time, but now we know we can change it.”

The tea party protests after Barack Obama’s 2009 inauguration started small, but they birthed a national movement that reset the Republican agenda and swept a wave of candidates into office in the 2010 midterm elections. Many credit the movement’s populist, anti-establishment sentiment with setting the stage for Trump.

Trump’s term as president starts off facing a much larger opposition. And, as many signs read at the Women’s March, “resistance is fertile.” We’ll see whether it’s fruitful.