To reinforce my point on the post-convention polling:
http://www.usatoday.com/news/politic...ll-kerry_x.htm
"Analysts say the lack of a bounce may reflect the intensely polarized contest. Nearly nine of 10 voters say their minds are made up and won't change. "The convention, typically a kicking-off point for a party, is now merely a reaffirmation" of where voters stand, said David Moore, senior editor of the Gallup Poll."
Another thing worth noting-- One signifigant difference between conventions before and after 1972 is the actual importance of the convention. Leading up to 1972, prior to the McGovern-Fraser electoral reform committee, the conventions actually had an impact. Delegates decided candidates, runningmates, and it gave people who watched a feeling of participation.
Now, in the era of front-loaded primaries, the conventions are meaningless. Hell, the networks didn't even carry most of the DNC. The assumption made of the "bounce" is that people who were undecided watch, fall in love, and then voice their feelings on the matter. Now, we knew John Kerry was the "presumptive candidate" in March. The electorate is polarized, pissed, and ready to roll. That, IMO, explains the lack of bumpage. :/