But movements usually matter more in generating opposition than in formulating alternatives; they typically function more as a red light than green. It’s difficult, for instance, to see Trump’s rise as a policy victory for the Tea Party movement. Trump’s agenda on several fronts, like infrastructure and health-care spending, could even revive the “big-government conservatism” of George W. Bush that infuriated Tea Partiers. Still, by creating demand for a more militant party, the movement reconfigured the GOP and helped pave Trump’s bellicose run to its nomination.

If it becomes a sustained movement, the women’s march might similarly reorient Democrats. Democratic elected officials remain divided over the right balance between confronting and cooperating with Trump. Privately, some leading Democratic strategists worry that Senate Minority Leader Chuck Schumer, despite some forceful criticism, will lean too much toward making deals with Trump, rather than working to systematically mobilize resistance and limit his support—as Senate Republicans, under Tea Party pressure, did against Obama.

Some deal-making may be unavoidable since Schumer must worry about protecting 10 Democratic senators facing 2018 reelection races in states Trump carried. But Saturday’s marches—like the Tea Party uprising—signaled that the passion in the party tilts decidedly toward resistance. Post-inaugural polls reinforce that conclusion. In the Gallup Poll this week, Trump became the first newly inaugurated president to enter office with a positive job rating from less than half of Americans. And just 14 percent of Democrats said they approved of his performance, while 81 percent disapproved. That was by far the lowest initial approval rating for a new president from voters in the opposite party. Bush, at 32 percent, marked the previous low.