In 2001, Seattle-based photojournalist Melina Mara began photographing the 13 female senators who held office that year. More than 35 of her black-and-white documentary photographs were exhibited recently at the Smithsonian's Arts and Industries Building.

"Changing the Face of Power: Women in the U.S. Senate," on view from May 22 through Sept. 7, presented images of 15 women senators at work on...