If a Marine spots two men in his battalion kissing off-duty at a shopping mall, he should react as if he were seeing a man and woman. If he turns on the television news to see a fellow Marine dressed as a civilian and marching in a parade with a banner that reads, "Support Gays and Lesbians in the Military!" he should accept it as a free right of expression. Prescriptions for those possible scenarios are being played out at Marine bases as the military prepares to allow gays to openly serve, ending a 17-year-old policy commonly known as "don't...