We knew that the 116th Congress was going to be the most diverse in history, with 102 women, many more openly gay members, more blacks, more Latinos, the first two female Native Americans, a Somali immigrant and the first ever Palestinian American woman elected to the House. But it was an altogether different thing to actually see that blazingly colorful diversity assembled under the portraits of the older white men who have lorded over the House of Representatives for so long.

As Nancy Pelosi made her way through the chamber to reclaim the speaker’s gavel, stopping after almost every step to receive a hug, it was a very emotional scene and the first time since Donald Trump’s election that I felt lightness and happiness radiating from the Capitol.

'Remarkable': the two photos revealing the divide in Washington Read more

And color. Deb Haaland of New Mexico, wearing a traditional Pueblo dress, was on the verge of tears as she embraced Sharice Davids of Kansas, a member of Ho-Chunk Nation. They are the first Native American women to serve in the House. Openly gay, Davids is also one of the record number of LGBTQ members of the chamber. Nearby, Ilhan Omar, a Somali immigrant from Minnesota, was resplendent in her white and gold hijab. Rashida Tlaib of Michigan, chose a copy of the Qu’ran to swear herself in as the first Palestinian American woman to serve in Congress. (The Qu’ran once belonged to Thomas Jefferson).

When Pelosi joined the House in 1987, there were only 23 female members. As of Thursday, there are 102, nearly 90% of whom are Democrats. It was striking when Pelosi passed a row that included Democratic representatives Alexandria Ocasio-Cortez, Barbara Lee, Jahana Hayes, Lauren Underwood and Sheila Jackson Lee, all women of color.

That rainbow was only visible on the left side of the dias – the Democratic side. On the right, where the Republicans sat, there was still the usual sea of suits worn by mainly older white men.

They will be a formidable force, trying to stymie Pelosi at every turn and frustrate the new, younger activists who are such an important part of her governing coalition. But change was everywhere on Thursday, from the line outside the women’s bathroom off the House floor (only gained in 2011) to the fans who practically overwhelmed Ocasio-Cortez outside Pelosi’s office.

Facebook Twitter Pinterest Nancy Pelosi takes a selfie with female House Democratic members outside the US Capitol. Photograph: Saul Loeb/AFP/Getty Images

There were, naturally, some sour notes. This was Washington, after all. Liz Cheney’s attempt to get a “Build That Wall” chant going, some stony Republican grimaces, and, lowest of all, a tape from Ocasio-Cortez’ college days of her dancing on a rooftop that was put up on Twitter by a rightwing troll. There was also the false suggestion that she wasn’t really from the Bronx.

“Here is America’s favorite commie know-it-all acting like the clueless nitwit she is,” read the post, with the user, who has since deleted their account, claiming it was a “high school video of ‘Sandy’ Ocasio-Cortez”.

It will be scintillating to watch Pelosi's moves and how the White House reacts

It’s frustrating in a post #MeToo world that women in power are still caricatured as inauthentic. Trump’s sneers at Elizabeth Warren, calling her Pocahontas, are meant to portray her as a phony, faking her ethnic roots. Pelosi, and, of course, Hillary Clinton, are often portrayed as stiff and inauthentic. It frightens the rightwing to see urban liberals like Ocasio-Cortez amass real followings and assert their growing power. So the rightwing tries to take them down with hackneyed caricatures and doctored tapes.

In the case of the dancing tape of Ocasio-Cortez, the attempted attack completely backfired.

Of course, the dancing tape went viral and clearly increased her popularity on social media and enhanced her status as a young sensation on Capitol Hill.

And she hit back in the best way, with humor. “You hate me cuz you ain’t me, fellas,” Ocasio-Cortez said. Then she quickly made a new video of herself dancing outside her new congressional office. In the lighthearted, 11-second clip, she dances along to a line from Edwin Starr’s classic Motown hit War: “What is it good for? Absolutely nothing,” she sings (or lip-syncs), pointing half playfully, half defiantly at the camera before bursting into laughter and flinging herself through the door of her office as if she had occupied her seat on Capitol Hill for years, not 24 hours

Play Video 0:56 'Congresswomen dance too': Alexandria Ocasio-Cortez hits back with new video

Thursday felt like the start of something truly new and important. It was clear that it rattled the president, as he ranted about calling a national emergency to get his wall built and said he was willing to let the government showdown go on forever.

Pelosi is a great strategist and she’s already outmaneuvered the president on the wall. She has talked of working with rational Republicans and extending a hand of friendship. She knows exactly what she needs to put together a winning vote. It will be scintillating to watch her moves and how the White House reacts.

It’s a new day and it’s not Trump’s Washington any more.