One reason I think that Ryan is f'd in the debate with Biden is that he now deals with a more restrictive media narrative. Biden's narrative is that he is prone to embarrassing gaffes. For the most part these gaffes are harmless and they are something he should try to avoid anyway. Ryan however is now seen as a liar and will have the veracity of his claims checked and held to standards that he is not used to. His arsenal of bs will do him far less good in the debates than it has done him in the past.