The Republican ticket-mates know perfectly well that being honest about their policies and platform would make it impossible for them to win a general election

Biden’s plan for dealing with Lyin’ Ryan was perfect: Laugh and scoff every time the congressman said something absurd. Treat a joke, in other words, as a joke. As Matt Taibbi commented: “He was absolutely right to be doing it. We all should be doing it. That includes all of us in the media, and not just paid obnoxious-opinion-merchants like me, but so-called ‘objective’ news reporters as well. We should all be rolling our eyes, and scoffing and saying, ‘Come back when you're serious.’"