President Trump and first lady Melania Trump blow a whistle to start an egg roll during the annual Easter Egg Roll on the South Lawn of the White House. (Olivier Douliery / Sipa Pool/European Pressphoto Agency)

The two sisters and their kids rolled into Washington on Monday from southwestern Virginia, eager to take part in a uniquely American tradition: the White House Easter Egg Roll.

One sister voted for President Trump; the other for Hillary Clinton. But it didn’t really matter to them who occupies 1600 Pennsylvania Ave. right now.

“This isn’t about politics right here,” said Stacy Moland, 47, the Trump voter. “We just want to see the White House.”

And that was it in a nutshell — or maybe an eggshell — on Easter Monday. About 21,000 parents and kids descended on the White House lawn, which actually belongs to all of us, regardless of party affiliation or lack thereof.

This beautiful, white-columned mansion really is the people’s house. The Trumps and the first families who preceded them are temporary residents. And the Easter Egg Roll, with a rich tradition that dates to 1878, transcends the polarizing politics of our time.

Or at least it did for Moland and her crew from Smith Mountain Lake, who won coveted tickets through a lottery and all wore matching leggings speckled with Easter eggs and pink shirts that read “Hangin’ with My Peeps.”

Doyon Hwang wasn’t a Trump voter, either. “But the husband is,” she said, pointing to the exhausted dad laden with eggs and Peeps and posters. They both love the Americana of the White House tradition, even if they both don’t love Trump. And they traveled from New Jersey for the event, just like last year, for the Obama family’s last Easter Egg Roll.

Then there was the gang from Rockville, financial adviser Laurie O’Toole and airport screener Barbara Compano. Most of the six girls with them are seriously ­anti-Trump.

“A friend of mine who wasn’t going told me I should throw the eggs at Trump if I saw him,” O’Toole said.

“But you know what?” Compano interjected. “It’s history. This is America, this is history, and this event is for the kids.”

It was easy to miss the political civility at the Easter Egg Roll. Because at first glance, the event looked as if it could have been a Trump campaign rally.

There were plenty of people sporting Trump’s signature “Make America Great Again” caps as they lined up for the 139th Egg Roll. The souvenir stands around the place were selling Donald Trump T-shirts at a good clip. And when it began to rain, as it did during Trump’s inauguration, a field of black Trump Hotels umbrellas bloomed across the landscape.

And it’s true that of the four administrations’ worth of Easter Egg Roll crowds I’ve seen, this was the least diverse. The historical photos of Easter Egg Rolls during the Johnson administration showed more diversity than this one.

The demographics of the crowd reflect who Trump voters are. And it was a remarkable contrast to the Easter Egg Rolls during President Barack Obama’s eight years in the White House, when the South Lawn looked much more like the tapestry that is truly America.

Those comparisons were inevitable.

One family lamented that this year, even after their son found the golden egg in an egg hunt, he wasn’t allowed to keep it. “They said we could buy one for $15,” the mom said.

“Last year? The winner of the egg hunt got a beautiful bag from Land’s End, embroidered with the White House on it,” someone else chimed in.

“Let me tell you, it was a mess compared to last year,” one mom said.

“The treats were better this year,” another added.

Last year, Shaquille O’Neal read “Green Eggs and Ham.” This year, Attorney General Jeff Sessions read “It’s Not Easy Being a Bunny.”

Last year, they had yoga. This year, it was tennis.

Last year, Michelle Obama wore sneakers and ran the obstacle race with kids. This year, Melania Trump wore a gauzy pink tea-length dress and drew pictures with children.

But everyone I spoke with was thrilled to be there.

“It’s the White House, this is an American tradition,” Chalaya Shorts, 27, who lives in the District, said as she walked with her daughter across the people’s lawn. “I’m so glad we finally got to go. First time.”

There were plenty of folks who refused to even consider going to the event this year. And their resistance was their rebellion.

But there were also those who went somewhat defiantly, who wouldn’t let the politics of the White House take away their American rituals.

It’s not his house. It’s our house.

Like Sara Ducey, a college humanities professor in Bethesda, who was wearing bunny ears and splashing in the rain with her granddaughter Hadley.

“My daughter did it when she was this old, so now it was Hadley’s turn,” said Ducey, who also blanched a bit when she described Sessions reading a bunny book to her grandchild.

“And we learned to say the first lady’s name,” she said to the little girl. “Mel-ahn-eeah,” they both said. She kept a straight face. She wasn’t going to engage in a smidgen of snark.

“This is the White House, it’s a tradition,” she said. “It’s bigger than politics.”

We’ve got it, America. Forget about the red hats vs. the pussyhats, and aim for the bunny ears.

An earlier version of this column referred to 44 first families who preceded the Trumps. This number is incorrect and has been removed.

Twitter: @petulad