“Our next guest needs no introduction,” Rep. Doris Matsui (D-Calif.) told the crowd gathered in the atrium of the National Portrait Gallery on Thursday night. “A former first lady …” Excited murmurs start growing in the audience gathered to celebrate the museum’s newest exhibition, “Votes for Women: A Portrait of Persistence,” ahead of next year’s 100th anniversary of the 19th amendment. A younger girl turns to her friend. “Oh, my God. … Do you?” “A former secretary of state,” the Democratic congresswoman from California continues. “Hillary?” another guest excitedly whispers, eyes widening. Then Matsui hits the nail on the head:...