The academic study of black Republicans is booming. Last year, Leah Wright Rigueur, a historian at Harvard, published “The Loneliness of the Black Republican,” a spirited study of conservatism, politics and race. Now we have Joshua D. Farrington’s “Black Republicans and the Transformation of the GOP” and Corey D. Fields’s “Black Elephants in the Room.” Other books have been published, and more are on the way. We may soon have more books on black Republicans than actual black Republican voters.