Joe Biden appealed to Democratic partisans, firing them up by attacking and, even more often, smirking at Paul Ryan’s arguments. But smirks only work when your audience starts off agreeing with you. That would be the case with strong Democratic partisans, but it’s not at all that clear that it appeals to Independents, or to those who are undecided or moveable. He was trying to dismiss Ryan’s arguments as ridiculous, in line with Democratic talking points that no rational person could possibly agree with him, but I think that only works with people who are already convinced. He may have increased Democratic voters’ enthusiasm—down in the dumps after Barack Obama’s performance eight days ago—but he didn’t do much in the way of converting those who are not already converted.