A legal expert is calling for a leadership overhaul at the Smithsonian’s National Museum of American History (NMAH), arguing the museum has embraced a negative, "self-loathing" portrayal of the nation’s past."I think this is part of a broader effort by radicals on the left to redefine the history of the United States and reframe it in an oppressor-versus-oppressed narrative," Cully Stimson, a senior legal fellow at the Heritage Foundation and former assistant U.S. attorney for Washington, D.C., told Fox News Digital."Instead of looking at American history chronologically with all the triumphs...