"Law & Order" star and former U.S. senator Fred Dalton Thompson is considering a bid for the White House that would test whether Hollywood can once again launch a Republican to the world's premier political stage. His interest, confirmed in a brief interview this week, is generating buzz in Washington. He was third among Republican-leaning voters in a recent Gallup-USA Today survey, behind Sen. John McCain (Ariz.) and former New York mayor Rudolph W. Giuliani and ahead of former Massachusetts governor Mitt Romney. The onetime senator from Tennessee is known to many Americans for playing New York District Attorney Arthur...