I do not buy the screed that Republicans are out to supress the black vote; the RNC is trying to get the black vote out so they can vote Republican!
I believe the difficulties in this election will entail voter surge. I believe that the local municipalities in Florida sucked. This year, I believe many other municipalities across the country will be bursting at the seams--and all it takes is one woman who stands in line for an hour and then has to leave to pick up her kids for someone to shout, "DISENFRANCHISEMENT."
This is where I believe monitors might actually benefit the electoral process. They will notice the counties are not prepared for the voter surge, not that someone is intimidating anyone.
If Bush wins, and even if he wins big, I believe we will suffer a spat of domestic terrorism. You can see evidence of that here and here.