Republicans nominated Barbara Comstock on Saturday to succeed longtime congressman Frank Wolf in Virginia's 10th Congressional District, turning away a slate of contenders who said they would be a more conservative choice. Ms. Comstock, a former Wolf staffer who represents McLean in the House of Delegates, will face Democrat John Foust in a November general election expected to draw national attention. Ms. Comstock had been the GOP front-runner since announcing her candidacy, winning support from most of the GOP establishment.