President Barack Obama marks the beginning of Passover with a Seder with friends and staff in the Old Family Dining Room of the White House, March 29, 2010. (Pete Souza/WHITE HOUSE)

As Jewish families across the United States sit down on Monday for the first night of Passover Seder, Arun Chaudhary will tell the very same joke about the “Hillel sandwich” that he’s told to the very same group of people for the past five years.

When Chaudhary makes his crack about the combination of matzoh, haroset and bitter herbs — “It was an amazing technological breakthrough for the Jews: You could fulfill your entire religious commitment with one sandwich” — the president of the United States will be sitting at the table.

What began in 2008 as an impromptu dinner thrown by three young aides in the basement of the Sheraton Hotel in Harrisburg, Pa., has become a ritual at the Obama White House. While it gets plenty of public attention — last week Israeli Prime Minister Benjamin Netanyahu’s wife, Sara, gave the Obamas a silver Passover Seder plate — the annual ceremony remains a private, fairly casual affair largely unchanged from its campaign origins.

And in a town where so many of the president’s meals — from lunch with the top two members of the House Budget Committee to dinner with a dozen Republican senators — involve a degree of political calculation, this one has few, if any.

“The Seder itself is something any Jewish family would easily recognize,” said Eric Lesser, who organized the 2008 meal while serving as the Obama campaign’s luggage wrangler.

Back then, Lesser, videographer Chaudhary and Herbie Ziskend, who did advance work for Obama, hatched a plan to celebrate Passover after spending months on the road. All three hail from the Reform branch of Judaism, says Chaudhary, whose mother is Jewish and father is from India. They’re “the outer-borough diaspora of Judaism, as opposed to experts in the Holy Land,” he said.

For that campaign-era Seder, Lesser’s cousin swiped several essentials from the University of Pennsylvania Hillel group (matzoh, Maxwell House Haggadahs and a couple of bottles of Manischewitz wine), which Lesser collected in Philadelphia and drove to Harrisburg.

Lesser and his friends didn’t expect then-senator Obama to show up. But he did, along with his friends Valerie Jarrett and Eric Whitaker.

“There were no cameras. This was not announced ahead of time,” said Lesser, who had mentioned the event in passing to Obama. “Nobody knew this was happening.”

‘It’s a good story’

Now, things are different. Obama is the first president to observe Passover in the White House: In his first official visit to Israel as president last week, he spoke about the personal significance this ritual holds for him. And he will also mention it in the official Passover message that the White House will release Monday.

“After enjoying Seders with family and friends in Chicago and on the campaign trail, I’m proud to have brought this tradition into the White House,” he said Wednesday during a speech in Jerusalem. “I did so because I wanted my daughters to experience the Haggadah and the story at the center of Passover that makes this time of year so powerful.”

As Nobel laureate and Holocaust survivor Elie Wiesel said in an interview, it’s not surprising Obama would be drawn to the holiday.

“It’s a good story. It begins in slavery and ends in freedom,” Wiesel said, referring to the retelling of the liberation of the Israelites in ancient Egypt. “This is a chance for a family to gather and tell what happened once upon a time.”

The president and his former aides are emotionally attached to their own improbable Passover story: that they pulled off the celebration at one of the low points of the 2008 campaign, when Hillary Rodham Clinton had won Ohio and looked poised to win Pennsylvania. After the group made the pledge that traditionally concludes the modern Seder — “Next year in Jerusalem” — Obama declared “Next year in the White House!” And he fulfilled that promise.

The president’s Passover guest list changes a bit each year, though it always numbers around 20. Jarrett, who remains one of Obama’s top advisers, comes most years, as does State Department spokeswoman Jennifer Psaki. They still use Haggadahs first produced in the 1930s by Maxwell House coffee (Wiesel quipped he’s “so disappointed” they don’t read from the version he penned), and Ziskend still hides a piece of matzoh, the Afikomen, every year so Sasha and Malia Obama can hunt for it.

“My strategy is just to find a creative place and hope the Secret Service doesn’t give any hints,” Ziskend explained.

The White House ceremony in the Old Family Dining Room does have a distinctly presidential feel to it: The participants eat on the Truman china, in tribute to the first president to recognize the state of Israel, and read the Emancipation Proclamation after they’ve finished recounting the Passover story.

The menu is less formal than the setting. It includes family recipes the White House chef prepares. This year it will include matzoh ball soup, brisket, kugel, meringue with raspberry ganache and, most likely, vegetables from the White House garden. Lesser always offers up his mother’s carrot souffle, while Ziskend contributes roast chicken recipes from both of his grandmothers, so as not to favor one.

Old friends reconnect

When the rite began, all three men were in their early 20s and unmarried, and their lives revolved around Barack Obama. Now two of them are married — Chaudhary has two kids, while Lesser’s wife is pregnant — and none of them work for Obama anymore. Lesser is in his second year at Harvard Law School, Chaudhary works for the progressive communications firm Revolution Messaging, and Ziskend works at the D.C.-based investment firm Revolution LLC. (The companies are unrelated.)

As a result, those gathered around the table will likely spend the beginning part of the dinner catching up. Jarrod Bernstein, who served as the White House Jewish liaison from October 2011 to February and attended last year’s Seder, recalled that “like every Seder, there’s a moment where you have to bring the table back to order.”

Bernstein, who will observe Passover with his wife, 2½-year-old son Jake and in-laws, said the White House ritual has already changed how he celebrates the holiday with his relatives. They now read the Emancipation Proclamation at the end, and Bernstein said the way Obama teaches his daughters about the Haggadah “will influence how I will be teaching my son about Passover one day.”

When the three young men who started the White House tradition have suggested altering aspects it — Chaudhary raised the prospect one year of not doing his Hillel sandwich routine — Obama has balked.

“You gotta make the speech,” he recalled the president telling him. “The speech is your thing.”

Even though the president’s reelection has given the ritual a new lease on life, they also now can predict when it will end.

“I have not reflected on what happens in 2017,” Ziskend said, pausing for a moment. “Maybe we’ll do it in Jerusalem.”