One winter night in 1924, a 19-year-old named Dorr Legg snuck away to a “charming park,” where he had his first sexual experience with another man, something he had been desiring—and studying—for several years. Born in a large home overlooking the campus of the University of Michigan in Ann Arbor, Legg came from a long line of Republicans: His family had been active in the GOP since its first convention in their state in 1854. Like many Midwestern Republicans, his father deplored Wall Street and the fat-cat bankers of the Northeast, even if they largely belonged to his political party; he taug…