It takes advocacy to get even the worthiest subject on the face of a U. S. postage stamp.

For example, take abstract expressionism, saluted Thursday with the unveiling of a new series of commemorative stamps in Albright- Knox Art Gallery, which owns four of the 10 paintings featured.

The cause was championed by Joan Mondale, who nominated the mid-20th century art movement as a member of the Citizens’ Stamp Advisory Committee of the U. S. Postal Service, said David E. Failor, the agency’s executive director of stamp services, after the first-day-of-issue ceremony.

Known as “Joan of Arts” in Washington, D. C., when her husband, Walter, was vice president from 1977 to 1981, Mondale began lobbying committee members on abstract expressionism’s behalf three years ago, Failor recalled.

About 50,000 ideas for stamps are submitted each year, but the vast majority are rejected. Just 20 to 25 new series will be issued in 2010, said Linda Kingsley, Postal Service senior vice president for strategy and transition.

Mondale’s background as an arts advocate, and the presence several committee members grounded in history, arts and design, helped her carry the day for abstract expressionism, Failor said.

It was then up to Ethel Kessler, the agency’s art director, and Jonathan Fineberg, University of Illinois art historian, to select paintings for the stamp series from the movement’s extensive oeuvre.

They eventually settled on the Albright-Knox icons — Jackson Pollock’s “Convergence,” Mark Rothko’s “Orange and Yellow,” Robert Motherwell’s “Elegy to the Spanish Republic No. 34” and Arshile Gorky’s “The Liver Is in the Cock’s Comb” — plus works by six other artists represented in the Buffalo gallery’s collection: Hans Hofmann, Clyfford Still, Barnett Newman, Adolph Gottlieb, Willem de Kooning and Joan Mitchell.

That the Postal Service launched the series in Buffalo reflects not just the predominance of Albright-Knox paintings but the gallery’s reputation as home of the world’s finest abstract expressionist collection.

It also underscores the wisdom of the late Seymour H. Knox Jr., who bought most of those works years before the movement or individual artists were noticed by other collectors, Albright-Knox Director Louis Grachos told the audience that packed the auditorium for the first-day-of-issue ceremony.

The story is that “the paint was still wet on the canvas when they came into the collection,” Grachos said of the Knox acquisitions.

After the event, dozens of stamp collectors lined up in the gallery gift shop to buy the abstract expressionist stamps, printed at Ashton Potter USA Ltd. in Amherst.

Other customers have 60 days to obtain the first-day-of-issue postmark by mail. Stamps can be purchased at postal branches or by visiting

www.usps.com/shop

or calling (800) STAMP-24.