This quote was recently posted on the wall of one of my favorite local bakeries: “Sometimes you have to fight the battle more than once before you win.”  Timely advice from former British Prime Minister Margaret Thatcher. The battle-tested Thatcher once declared she “had no time for women’s lib.” Likely, she would not have embraced the 100 thousand women who marched last week in London’s Trafalgar Square in sisterhood with women marchers in Washington, D.C. and the world over. More than three million women took to the streets—many of them with signs and chants expressing anger and frustration about having to fight—again—for the women’s rights they thought they already had.

By several measurements the Washington, D.C. March was confirmed as one of the largest demonstrations in the U.S., period. It was thrilling to see the multitudes that showed up to take part in both the big city marches and the smaller ones in heartland cities like Wichita, Kansas and St Louis, Missouri. Empathetic men joined in, but this was first and foremost a women’s march. The diverse crowd—all ages, backgrounds and races, moved me. Even when a political difference threatened to upend the big tent, march organizers worked hard to include all comers. They told anti-abortion proponents they were welcome, while at the same time making it clear that these marches supported a pro-choice abortion policy. The marchers put forward a broad spectrum of issues, including reproductive rights, criminal justice reform, childcare and equal pay. They were unified not by a single issue, but a singular mission: we will be heard.

So many of the women who came had never taken part in a march, or any kind of protest. Veteran activists know that a march is just the beginning; that the real demonstration of power comes from public pressure beyond the high of one moment. The real question: is this Woman’s March a powerful moment, or is it a movement?

If it is to be a movement, the jubilant marchers would do well to understand that constructive dissent is a long game, sometimes a really long game, with no guarantee that even some of the goals will be achieved. That’s what the civil rights marchers knew, what the antiwar marchers knew, and why the Standing Rock Sioux are still in the tent city they created to block the Dakota pipeline. This one-day show of female force is already in the history books. But for this moment to become a movement, the marchers must be committed to, in Margaret Thatcher’s words, “fighting the battle more than once.” The photo of one older women’s annoyed acceptance of this reality heartens me. Her hand-lettered poster read, “I can’t believe I still have to protest this [expletive].”