WASHINGTON — President-elect Barack Obama has returned to the White House for a private sit-down with President George W. Bush, less than two weeks before their official transfer of power.

Obama was to meet with Bush for about 20 to 30 minutes for a discussion likely to cover the Middle East and the struggling economy. The two leaders also met at the White House on Nov. 11, shortly after Obama’s election win.

Obama has sought to strike a balance as the power curve bends his way. Before even taking office, he is publicly rallying Congress behind a massive economic stimulus plan. But he remains deferential to Bush on foreign affairs and will not comment on Israel’s raging conflict with Hamas on grounds that doing so would be dangerous for the United States.

After their talk, the two men will be part of a tableau not seen since 1981: the president and every former president together at the White House.

Bush, picking up the idea from Obama, was hosting a noon lunch for the incoming president and three former presidents: Bill Clinton, George H.W. Bush and Jimmy Carter. It will be the first time all the presidents have gathered at the White House since 1981.

“You can’t have two administrations running foreign policy at the same time,” Obama said at a news conference just ahead of his meeting with Bush. “You simply can’t do it.”

White House press secretary Dana Perino said that Bush and Obama have quickly developed a good relationship, in part because “they’ve been able to keep their conversations private.” But she said the two leaders are all but certain to review the Middle East and the economy.

Vice President-elect Joe Biden also held a private meeting with former President Bush at the White House this morning.

Considering the bond they hold in history, U.S. presidents gets together infrequently, particularly at the White House. And when they are in the same room, it is usually for a milestone or somber moment — a funeral of a world leader, an opening of a presidential library, a commemoration of history.

Not this time.

The White House says Obama suggested the idea of a presidential gathering when he met Bush in the Oval Office in November. And Bush went for it.

“It’s going to be an interesting lunch,” Bush told an interviewer recently. When asked what the five men would talk about, Bush said: “I don’t know. I’m sure (Obama’s) going to ask us all questions, I would guess. If not, we’ll just share war stories.”

They have plenty of those, political and otherwise. Their paths to power have long been entwined.

Carter lost the presidency to Ronald Reagan, whose running mate was George H.W. Bush. Bush later won election but lost after one term to Clinton. Then Bush’s son, the current president, defeated Clinton’s vice president, Al Gore. And this year Obama won after long linking his opponent, John McCain, to Bush.

Those campaign rivalries tend to soften over time as presidents leave the White House and try to adopt the role of statesmen — although Carter, even as an ex-president, has had some critical public words for the current president’s foreign policy.

All five men were to pose for a group photo in the Rose Garden, but a January rainstorm scrapped that plan. So the noontime photo opportunity — to be the media’s only glimpse of them — was moved indoors to the Oval Office instead. The presidents and Obama will then have lunch for an hour in a private dining room off the Oval Office, where no one else was expected to join them.

“All of us would love to be flies on the wall and listening to that conversation,” White House press secretary Dana Perino said.

She added, “I’m sure their conversation will range from everything from personal experiences here — I’m sure they’ll talk a little bit about raising children in the White House, raising children when you’re a public figure and how to protect them.”

It was also quite possible, given the heavyweights in the room, that the topics could be far weightier. Both Bush presidents, Clinton and Carter have had extensive experience coping with Middle East strife; Obama is about to inherit a bloody conflict between Israel and Hamas.

The rare presidential joint appearance also offered Bush, who ends his two terms deeply unpopular, to again show he is rising above the fray.

Already, the White House is brimming with symbolism of a change in power. The construction of inauguration-parade viewing stands is accelerating on Pennsylvania Avenue, right in front of the White House. Perino said Bush and first lady Laura Bush have “been working to box things up.”

Bush, Carter, Clinton and George H.W. Bush were last together in January 2007, to attend President Gerald Ford’s funeral service in Washington

The last White House event to draw the former presidents was a November 2000 celebration in honor of the White House’s 200th anniversary. But one of the former presidents, Ronald Reagan, who was afflicted with Alzheimer’s disease, was unable to attend.

All the presidents were last at the White House in 1981: Richard Nixon, Ford, Carter and Reagan, who was president then. The three former presidents were there before leaving as part of the U.S. delegation to the funeral of Egypt’s Anwar Sadat, who had been assassinated.

On that day, all the presidents stood in a circle inside the White House, discussing news of the world. The dominant topic? The Middle East.

They were joined in the conversation by one other leader — Vice President George H.W. Bush, who later went on to join their presidents’ club.