Free admission to the Smithsonian Institution's museums and National Zoo stands out in the District, where everything has its price. But with deteriorating buildings, a maintenance backlog in the billions and fewer public dollars to spare, one member of Congress says no fees makes no sense. "I cannot understand why we don't charge a fee," Rep. James P. Moran, Virginia Democrat, said after hearing House testimony about insufficient funds for repairs. The Smithsonian in its 160-year history has never charged to visit the museums, stocked with displays of everything from dinosaur bones and the Hope Diamond to the original Star-Spangled...