This
article, by David Bernstein in the Boston Phoenix, describes in calm detail how the Republicans messed with the vote in Ohio in
public, low-tech ways, and it attempts to quantify the effect on the outcome. The author argues that it's highly plausible that more Ohioans tried to vote for Kerry than for Bush. There are eye-opening details I haven't seen elsewhere.
For example, everyone expected high turnout, but the Republicans in charge of the process reduced the number of polling stations. They used the excuse that they were assuming that with new high-tech voting machines the voting would go much more quickly, but in fact, although the state got $133 million from the Federal government to upgrade their machines, the new machines were never bought! Blackwell gave the excuse that he didn't trust security in the new machines.
The upshot is that they cut down on the number of precincts, didn't upgrade the voting machines, and got higher turnout. The result was predictable: up to six-hour waits in some places, with discouraged voters turning away (rather than be fired for long absence from work).
The article also shows that the reduction in the number of precints occurred in Democratic counties, not Republican ones.
I don't know whether or not vote-counting fraud occurred: There's a lot of work going on on that question, and it will be a while (if ever) before we know the answer for sure. But this is a set of actions that are a part of the public record that are clearly outrageous. This stuff should be plenty for people to grab their pitchforks and torches and head for the town square in protest.
(Note, BTW, related diary on ongoing Blackwell mischief.)