On June 8, 1967, the Israeli military machine-gunned, bombed and torpedoed the U.S.S. Liberty, an American vessel floating off the Sinai Peninsula, killing 34 service members. Those facts are not in dispute. But almost everything else about the attack is driving a wedge through the MAGA movement. On one side are prominent voices like the podcaster Ben Shapiro, Senator Ted Cruz of Texas and Rich Lowry, editor in chief of The National Review. They insist the attack on the Liberty was a tragic case of mistaken identity amid the chaos of the Six-Day War, a conclusion shared by a U.S....