The culture wars returned to the Supreme Court on Tuesday, this time in a battle over whether public schools in Maryland must allow parents with religious objections to withdraw their children from classes in which storybooks with L.G.B.T.Q. themes are discussed. In a long, lively and sometimes heated argument that gave close consideration to a handful of books for young readers, questions from members of the court’s six-justice conservative majority indicated that the parents were very likely to prevail. “The plaintiffs here are not asking the school to change its curriculum,” Justice Samuel A. Alito Jr. said. “They’re just saying, ‘Look, we want out.’ Why isn’t that feasible? What is the big deal about allowing them to opt out of this?” Justice Brett M. Kavanaugh noted that the school board had initially allowed parents to withdraw their children when the books were to be discussed but reversed course.