It was as if a different America pushed back as the turnout at Women's Marches in cities across the country last Saturday - Mr Donald Trump's first full day as president - swelled to some two million, exceeding expectations.
In Washington, the number was at least double that at last Friday's inauguration. Metro trains heading to stations near the main protest site were packed and services were delayed as stations became overwhelmed.
The idea of marching became superfluous as the numbers grew.
The question, analysts say, is whether the broad-based, largely organic protest will become a sustained movement, fuelled by the rise of Mr Trump, who last year ran an abrasively nationalist campaign marked by controversial remarks about women.
Given the record numbers that turned up, and their age profiles - a large number were mothers with teenage daughters, or students and young professionals - many are optimistic.
"I think the Women's Marches served to inspire hundreds of thousands of new people in civic engagement," Ms Rachna Choudhry, co- founder of POPVOX.com, a non- partisan platform that tracks congressional activity, told The Straits Times. "The frustration and anger around the election results at the marches seem to have transformed into holding Trump as president accountable."
Speakers and marchers came from across America's ethnic and religious spectrum, many of them wearing pink, knitted "pussy hats" - a reference to a vulgar comment that Mr Trump made in 2005 - and chanting, "We need a real leader, not a creepy tweeter".
Celebrities turned out in droves - including Alicia Keys and Madonna in the US capital and Joan Baez in San Francisco.
Actress America Ferrera, a first- generation American born to parents from Honduras, who has been active at Democratic Party events, said: "The President is not America. His Cabinet is not America. Congress is not America. We are America. And we are here to stay."
Reacting to the marches, Mr Trump said on Twitter: "Watched protests yesterday but was under the impression that we just had an election! Why didn't these people vote? Celebs hurt cause badly."
Dozens of organisations, focusing on issues from women's, minority, labour and LGBTQ (lesbian, gay, bisexual, transgender and questioning) rights to immigration and the environment, were involved.
They included Planned Parenthood, which provides health services to women - and men - but has long been a target of pro-life conservatives as it offers abortions. Planned Parenthood may lose federal funding under the new administration.
A large number of protesters took part as individuals or with friends and families, in many cases travelling long distances.
A man who declined to be identified because he works for a federal government agency said: "Today is a beautiful day, an American day."
Mr Trump said in another tweet: "Peaceful protests are a hallmark of our democracy. Even if I don't always agree, I recognise the rights of people to express their views."
Professor Glenn Altschuler of Cornell University said "the test for the strength and durability of the movement will come soon" as Congress debates defunding Planned Parenthood and repealing Obamacare.
"Donald Trump may have awakened a sleeping giant," he told The Straits Times through e-mail.
But he cautioned that the impact of thousands in the streets may be limited. "It is by no means clear that massive protest rallies will influence the Republican majorities in both Houses of Congress," he said.