The American flag is a potent symbol of pride and patriotism, of promises made and promises unkept, of victory (the raised flag at Iwo Jima) and tragic loss (the flag-draped coffin of slain President John F. Kennedy). It is woven into our national psyche, a design element that signals home and citizenship. An American flag planted on suburban porches overlooking pristine lawns was once a staple of New Yorker magazine covers and Norman Rockwell paintings, including his portrait of Betsy Ross mending a flag enfolded tenderly on her lap. This summer we will be getting more than the usual eyeful of Old Glory as the United States lumbers toward its 250th anniversary on July 4, a massive bombardment of red, white, and blue. To mark the semiquincentennial, Washington’s National Gallery of Art is presenting “American Icon: The US Flag in Art,” an exhibition of American artists ranging from “Pop Art Nun” Corita Kent and flag-variation virtuoso Jasper Johns to photographers Gordon Parks and Robert Frank investigating the meaning and aesthetics of the stars and stripes, the different messages conveyed through a playful change of color or a more somber monochromatic lens. Like any classic, the American flag is an inexhaustible image that retains its essential identity, a mute eyewitness to history. —James Wolcott