Oh yeah? Tell that to the Democrats in 1968
One, there were riots at the 68 convention. That's not what we are talking about here.
Two, you can't establish that Nixon won because of the Democratic convention.
You are leaping to unfounded conclusions.
I've said it before, I'll say it again. There is one thing that decides Presidential elections. The economy. Obama proves the point. The only way he could ever have won in 2008 is that the economy was perceived to be crashing, and McCain considered part of the incumbency.
If the economy is bad in November then anyone will beat Obama. All this hand-wringing about trivia is stupid.