What power the comma has! Its presence, absence, and position can cause the same series of words to mean either of the following ideas:
Yikes. Of course, listening to a recording of the statement in question, it seem unequivocal that Sen. Biden intended the latter meaning. What value the statement holds politically, I neither know nor care to comment about. Frankly, I'm not surprised to hear a Senator from one party impugn the viability of another party's presidential candidates. That falls under the flag of "business as usual".
The interesting issue is what Language Log points out: the transcription of this statement was made in one of two ways: the transcriber was either incompetent, malicious, or both. People think I'm being pedantic when I point out grammatical errors; I'd say that habit is more prudence than pedantry.
Perhaps my love for Encyclopedia Brown is partially responsible for my commawareness (like that new word?). Anyone who read that series religiously will recall a case rather similar to Sen. Biden's. One of Encyclopedia's friends phoned a girl's house and left a message for her with her younger sister. Transcribing the message over the phone, the sister misplaces several commas; the resulting message has the same words but a completely opposite meaning than the original. It's something along the lines of "I want to be your friend" becoming "I don't want to be your friend".
Friends use punctuation, in proper ways so; your words may have, meaning.