Mystifying. Republican presidential candidate Marco Rubio said Wednesday he would oppose a constitutional amendment allowing states to ban same-sex marriage after the Supreme legalized it nationwide, even though he disagrees with the landmark 5-4 decision.“I don’t support a constitutional amendment. I don’t believe the federal government should be in the marriage regulation business,” the Florida senator told reporters after a speech the Cedar Rapids Country Club in Iowa.“We can continue to disagree with it. Perhaps a future court will change that decision, in much the same way as it’s changed other decisions in the past. But my opinion is unchanged,...