In 1976, when he was director of the Central Intelligence Agency, future vice president and president George H.W. Bush sent a letter to Rolling Stone. The magazine had just printed his portrait, along with 69 others, as part of an ambitious project by photographer Richard Avedon titled "The Family."

"It was a pleasure having Mr. Avedon out here at CIA," Bush wrote. "I don't know if he was as scared to come out here as I was in posing for the great Avedon, but he sure has a neat way of putting his victims at ease and I enjoyed our short time together."

Posing for the great Avedon was a rite of passage for the powerful in the second half of the 20th century. Avedon's lighting was mercilessly even, revealing wrinkles while denying drama. His works offer a convincing illusion of what these people must really have been like.

In Avedon's portrait, Bush looks a bit more reflective than he does in most pictures. But it doesn't tell us anything that spy chief Bush didn't want us to know.

This photograph, along with all the other portraits Avedon did for the Rolling Stone project, is on view in the National Museum of Jewish History exhibition "Richard Avedon: Family Affairs." The exhibition also includes four group portraits, including a larger-than-life-size mural of poet Allen Ginsberg with members of his family. The exhibit originated at the Israel Museum in Jerusalem and consists mostly of items from its collection, though a few elements have been added for the Philadelphia showing.

The show is a deep dive into a few moments of Avedon's long career, which began with lively, imaginative fashion photography very different from what is on view here. The Rolling Stone portraits are relentlessly uniform, a bit less than 16 inches high and 13 inches wide. Like nearly all the portraits Avedon made, the subjects are posed against white paper, which literally blanks out any context. Avedon printed the edge of the negative, which gives each image a sort of frame. Indeed, one of the only points of contrast in the photos is whether the subject fits comfortably in the frame or expands to the edges.

In 1969, Avedon bought an 8-by-10-inch view camera that he used for all his subsequent portraits. This unwieldy device on its tripod was about as tall as Avedon, who stood to one side of it and was able to engage his subjects directly without the camera getting in the way. Nearly all his subjects were standing, as well. He made relatively few exposures.

The Ginsberg mural appears to have been taken in the aftermath of a catered affair. Members of the poet's family clutch drinks, slices of layer cake, and plates that seem to contain remnants from the buffet table, all carefully staged by Avedon. It is actually two exposures, which we know because Ginsberg stands, like a mismatched wallpaper pattern, at the seam. If we look closely, we see that Ginsberg's father, Louis, whose own book of poems was the reason for the 1970 celebration, appears twice in the mural. (A similar thing happens in Avedon's two-part group portrait of Andy Warhol's Factory. Actor Joe Dallesandro is completely nude on the left, and uncharacteristically clothed on the right.)

In the Ginsberg mural, the Beat poet provides an unlikely hinge, tying together the thoroughly conventional-looking yet disparate family. You know there are a lot of stories there, none of which is being told.

The Rolling Stone project is an amazing testament to Avedon's ability to get powerful people in front of his camera. It was originally conceived as a tie-in to the 1976 presidential election, happening 200 years after the founding of the United States and two years after Richard M. Nixon was forced to resign from office in the Watergate scandal.

In a short time, Avedon was able to photograph many members of the American elite - senators, cabinet members, corporate executives, political fixers, labor leaders, bureaucrats. Pete Rozelle, who built the National Football League as we know it today; Felix Rohatyn, the suave financier who saved New York from bankruptcy; and Arthur Burns, the chief of the Federal Reserve who was about to oversee the worst inflation in U.S. history - all are there. So is Jerry Brown, who was governor of California at the time, and is again today.

Many figures associated with Watergate are here. Nixon's secretary, Rose Mary Woods, wearing a fancy, very '70s print blouse, recoups a bit of dignity here; in her best-known photograph, she had contorted herself to show how she might accidentally have caused an 18-minute gap in a key portion of the Nixon tapes. Katharine Graham, who put the future of the Washington Post Co. on the line by pursuing the Watergate investigation, hangs her glasses just above her elbow and seems impatient to get on to the next thing. There is even W. Mark Felt, associate FBI director, later revealed to be Deep Throat, an important source for the Post's reporting.

At the time, "The Family" was a highly ambiguous title for such a project. Only a few years after the first two Godfather movies, many people, especially Rolling Stone readers, saw this convocation of the powerful less as a big national family than as a criminal conspiracy. Yet everyone showed up for the yearbook shot.

The exhibition includes a remarkable bit of film that suggests why. It was shot by the great documentary filmmaker D.A. Pennebaker at the opening of a 1964 exhibition of Avedon's work at the McCann Erickson advertising agency in New York. The exhibition, which features a variety of photographs at different scales seemingly just tacked to the walls, looks like more fun than the one we are in. And all those ad men smoking their pipes and drinking pull us into the real Mad Men milieu.

But the figure we can't take our eyes off of is Richard Avedon, who flows through the gathering, performing the dual roles of guest of honor and host with consummate grace. Everyone seems to be the object of his attention. That's impossible, but he had the charm to pull it off.

Art: AVEDON'S PEOPLE

Richard Avedon: Family Affairs

Through Aug. 2 at the National Museum of American Jewish History, 101 South Independence Mall East

10 a.m.-5 p.m. Tuesday-Friday

10 a.m.-5:30 p.m. Saturday and Sunday

Admission: $12; 65 and up and 13-21, $11; 12 and under, free

215-923-3811 or www.nmajh.orgEndText