WASHINGTON » When President Barack Obama invited President Francois Hollande of France for a state dinner, the White House drew up a list of 300 guests to honor the visiting leader and his partner, Valirie Trierweiler. Engraved invitations, with the presidential seal in gold at the top, were printed and set to be mailed.

But there was an unexpected development. Hollande’s relationship with Trierweiler blew up in the midst of revelations of an affair with a French actress he had secretly been visiting by motor scooter. Suddenly, Trierweiler was no longer France’s unofficial first lady and no longer coming to the White House. The thick ivory invitations with the words "the president and Mrs. Obama request the pleasure of" each guest’s company had to be quietly destroyed and new ones printed without Trierweiler’s name.

L’affaire Hollande has proved to be a dangerous liaison for the tradition-bound White House. Although it is not unprecedented, not many foreign leaders arrive at the executive mansion stag for the most formal and coveted gala in Washington, and even fewer split from their partners, legally recognized or otherwise, just weeks before the festivities.

For a few days, at least, the White House social office was left to wonder whether the other woman – identified by the weekly tabloid Closer as the actress Julie Gayet, 18 years younger than Hollande, 59 – would come in place of Trierweiler. (She will not.)

All of which has posed challenges for a White House staff already nervous about holding the first state dinner in nearly two years, and for haute cuisine-conscious French guests no less. There will be no traditional coffee or tea for the spouse with Michelle Obama, and the American first lady will have no one to escort to a local school as she has done with previous counterparts.

The turn of events in Hollande’s private life posed a number of questions for the White House as well: Who should be placed next to the president in the seat Trierweiler would have occupied? Would any of the entertainment be inappropriate? Should there be dancing if the romantically complicated guest of honor has no one to dance with?

"That may be a bit of a protocol debacle there," said Walter Scheib, the White House chef to Presidents Bill Clinton and George W. Bush. "It’ll be curious to see if he asks the first lady for a dance. That would be on the front of all the tabloids – Frenchman sweeps first lady off feet!"

The White House social office, discreet on all occasions and on this one as secretive as North Korea, will not say what accommodations it has made.

"The protocol is to pretend it doesn’t exist," said Craig Roberts Stapleton, who served as Bush’s ambassador to France. "This is not a subject that will be high on the talking points that will be given to President Obama."

The White House is nonetheless making an extra effort to put on display the nation’s historic and cultural ties with France. Obama will take Hollande to Charlottesville, Va., on Monday for a tour of Monticello, the home of Revolutionary America’s most prominent Francophile, Thomas Jefferson. Any separate spouse’s program that typically would have been arranged has surely been canceled.

The state dinner is Tuesday night, when the Obamas will host an extravagant, multicourse, black-tie event with government officials, business leaders, political fundraisers and celebrities. To allow a larger guest list, the dinner will be held not in the State Dining Room, which can handle about 135 people, but in a massive pavilion-style tent on the South Lawn, complete with chandeliers, that can hold 300.

Jeremy Bernard, the White House social secretary, is organizing the dinner under the direction of the first lady. He has brought in Bryan Rafanelli, the Boston-based event planner who orchestrated Chelsea Clinton’s wedding in Rhinebeck, N.Y., and whose website says he serves "some of the most successful people, companies and brands in the world."

The state dinner has long been one of the most celebrated of presidential affairs, "an event that also showcases global power and influence," as the White House Historical Association puts it. The first president to have one for a foreign leader was Ulysses S. Grant, who in 1874 feted King David Kalakaua of the Sandwich Islands, now known as Hawaii.

"There’s no substitute for being in each other’s home and developing a personal relationship," said Anita McBride, who was chief of staff to Laura Bush. "You reserve state visits for a circumstance when you want to promote the highest level of ceremony for your foreign visitor."

Few presidents used the events to as much effect as Ronald Reagan, who hosted 35 during his eight years in the White House, and the first George Bush, who hosted 21 in four years. Clinton hosted 23, but his two successors have been less enamored of the custom, both personally and politically, during times of war and economic turmoil. The younger Bush hosted only six, the same number that Obama has had so far.

Foreign leaders lobby for an invitation, calculating that such an event conveys stature back home.

The Chinese pressed Bush for a state dinner, but he agreed only to a luncheon. The Turks pressed Obama but had to settle for an official visit after complaints about domestic policies. For the first time in modern memory, one leader last fall actually canceled a state dinner, President Dilma Rousseff of Brazil, who was upset to learn she had been spied upon by the National Security Agency.

The few state dinners under Obama have been elaborate events and criticized for expenses that have risen with the number of guests and high-cost entertainers like Beyonci, who may waive their fees but still require equipment, lighting, technicians and even wind machines. Most famously, the dinner for India’s prime minister was marred by party crashers who were auditioning for a television reality show and made it inside the White House uninvited.

The French are always among the most high-pressure guests because of their culinary standards. Scheib recalled Hillary Clinton’s fretting over a visit in the 1990s.

"She was more anxious about that than any other dinner that we did," he said.

As it happens, Hollande is not the first French president to come alone. In 2007, his predecessor, Nicolas Sarkozy, surprised the Bushes just three weeks before arriving for a White House dinner that was not technically classified as a state visit by announcing his divorce from his wife, Cicilia.

"We really weren’t sure until a couple of weeks before the dinner whether she was coming or not," McBride recalled.

Still, it did not generate as much attention as Hollande’s love triangle has.

"I’m not sure it was quite this sensational," she said.

Obama and Hollande do not have a strong personal relationship, and the United States has been without an ambassador in Paris since last summer. But France has become central to U.S. foreign policy in Syria, Iran and elsewhere.

"Hollande has been a good foreign policy partner," Stapleton said.

While headlines may focus on protocol, policy experts say the meeting holds significance for the future of Obama’s agenda.

"It will be awkward, and it will be high drama," said Julianne Smith, a former national security aide to Vice President Joe Biden. "But nonetheless, I think what people will watch for is what’s the tone, what’s the relationship between France and the United States."

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