The Irish referendum—in which 66% of voters chose to allow parliament to legalize abortion—underscored the decadeslong decline of the Catholic church as a political force in that nation. It also accentuated a mirror image in Poland, the last major nation in Europe whose Catholic Church still dominates politics, society, and culture. Poland was once among the easiest places in Europe to get access to an abortion. Under Communism, ferries brought pregnant women from Sweden and Denmark for the procedure, which was free of charge. That changed at the end of the Cold War, when the Catholic church emerged as a...