One day in late April 1958, a young economist named Madeleine Tress was approached by two men in suits at her office at the U.S. Department of Commerce. They took her to a private room, turned on a tape recorder, and demanded she respond to allegations that she was an “admitted homosexual.” Two weeks later, she resigned.Madeleine was one of thousands of victims of a purge of gay and lesbian people ordered at the highest levels of the U.S. government: a program spurred by a panic that destroyed careers and lives and lasted more than forty years. Today, it’s known as the “Lavender …