Prosecutors are relying on a federal criminal statute that the U.S. Supreme Court has challenged as unreasonably vague, and a prosecutorial strategy that one legal expert described as “venturesome.” “I think it’s an aggressive prosecution, on facts that are not clearly distinguishable from everyday politics,” said John C. Jeffries Jr., a professor and former dean of the University of Virginia School of Law. “That’s not to say the governor’s conduct wasn’t stupid or sleazy — I think that’s clear,” Jeffries said, “but ...