Obviously we are all concerned with the manipulation of voting challenges started in the 1970s, but being ramped up by the Tea Party and others. Frank Pasquale at Balkinization points to an editorial in the NYTimes, and, of course there are many other links one could find. A common thread is that the lists and challenges are characterized by a zillion false claims.
Elizabeth Drew at the New York Review of Books put some numbers on this
Iowa, Florida, and Colorado tried to purge the voting rolls of suspected unqualified voters, but their lists turned out to be wildly inaccurate. Florida officials compiled a list of 180,000 people whose qualifications were questioned, but after voting registrars checked (some protesting the unfairness of the purge) only 207, or .0002 percent of the state’s registered voters, were found to be unqualified to vote.
Thus Eli's simple rule to shut the assholes down. For every challenged name, the challenger has to deposit $10 to cover the cost of investigation of the claim. If the claim fails, they forfeit the money. If it is correct they get the money back. If you challenge someone at a polling place and they show (even later) that they are legit, they get the challenge money ].