Maryland Governor Martin O’Malley has rejected an appeal from Baltimore’s Archbishop Edwin O’Brien, who urged him not to promote same-sex marriage out of “mere political expediency.” Responding to a personal letter from the archbishop, O’Malley—who is Catholic—said that he felt a moral obligation to change a law that produces an “unjust result.” Archbishop O’Brien wrote to O’Malley in July, warning him not to endorse a measure “that so deeply conflicts with your faith, not to mention the best interests of our society.” In his reply, the governor said that he has “a public obligation to try to change that injustice.”...