Of course, what is good for the country is irrelevant when it comes to electing our President. All that matters is how well the Republicans can convince people that the other guys are morally bankrupt and will raise their taxes. It doesn't matter how bad the economy gets, Americans, who never learned economics due to our underfunded education system, think that a promise not to raise taxes will protect their income and spending power (of course, they also believe that the theory of evolution means that people were sired by monkeys, so it's all relative). Democrats are going to start behind for that reason no matter what, so the issue then becomes how successfully the conservatives can smear the Democratic ticket. With Biden, they have some ammo:
1) He's an established plagiarist. Now Im sure most Americans do not consider plagiarism a crime on the level of say, marrying an unapproved person or removing a microscopic cell cluster from a womb to save countless lives, even though of course it is much, much worse, but it is still something the Reps can point to and say "Look! Integrity issues!" (and by the way, how come John McCain can completely abandon his suffering wife for a newer, richer model with no problem but John Edwards steps out for a one-off and its the end of his career?)
2) He's on record as supporting McCain over Obama.
One wonders why Democratic candidates don't think of these things when running against each other. This one is really bad and you can be sure we are going to hear about it all day long on FOX news.
3) He tends to put his foot in his mouth. Now in all fairness, the guy is 65 and had a couple of aneurysms, so you can forgive him for misspeaking every now and then, and he is charismatic enough to charm his way out of these situations most of the time, but it still gives me pause.
Will Biden hurt/help Obama? In the White House, a definite help. As far as getting elected, it probably won't matter one way or the other. Hopefully we'll get lucky and McCain will add Joe Lieberman to his ticket, since you can be sure the Fundamentalists won't stand for that.