If the demonstrations turn violent or ugly, watch for Republicans to sweep races from top to bottom. IMHO, you will see a lot of Democrats that have been on the edge now officially leave their party.
We have a Republican County Commission candidate that was a Democrat until last year and he said he could not take it anymore and became a Republican.
With Kerry heading the ticket, flyover country democrats have been shut out of the process. Heck Kerry came in 3rd here in OK.
If voters perceive this as a street attack upon the Republican convention by Democrats or Dem sympathizers, it very will may push swing voters to the Republican side. And if this happens, just watch the Dem spinmeisters go into action - "Oh, we TOTALLY disassociate ourselves from that unruly crowd." lol