A new exhibit at the Smithsonian's National Portrait Gallery is compelling its viewers to reflect on the roots of U.S. hegemony. "1898: Imperial Visions and Revisions" is a superbly presented and thought-provoking collection of portraits, paintings, political cartoons, old newspaper clippings, and other artifacts that tell the story of overseas expansion through the eyes of Americans and the people over which they would rule, after defeating Spain in a short war, in Puerto Rico, Guam, Cuba, and the Philippines. Congress annexed Hawaii against the will of Hawaiians the same year. At a time when the U.S. role in the world is subject to considerable debate, the exhibit -- co-curated by Kate LeMay and Taina Caragol -- confronts us with the controversial origins of America's global reach. Did you know an Anti-Imperialist League, whose members included Mark Twain and Andrew Carnegie, protested U.S. domination of overseas territory?