Charges of voter fraud have been growing in recent weeks, most notably with Republican attacks against an anti-poverty group known as the Association of Community Organizations for Reform Now, or ACORN.
The group, which has submitted more than 1 million voter registrations, has come under fire after several thousand of the submissions were found to be phony. But the intensity of the attacks from the Republican National Committee and Sen. John McCain's campaign has also raised questions about Republican motives.
Critics said that ACORN is part of an effort to steal votes and possibly throw the outcome of the election into doubt. Former Missouri Sen. John Danforth co-chairs the McCain campaign's Honest and Open Election Committee, and he said whoever loses on Nov. 4 could feel cheated and want to challenge the results in court.
"If there are a number of states where the election is close and there have been many, many people registered by this organization, ACORN, and where there are numerous cases of fraudulent registration, then the contest could go on for a very long time," he said.
Rick Hasen, an election law expert at Loyola Law School in Los Angeles, said he thinks Republicans are leveling the criticisms in case they lose.
"I think this is just part of a kind of a long-term Republican strategy to play up allegations of voter fraud," Hasen said. "As a kind of insurance policy in case there's a very close election."
He said there is little evidence that voter registration fraud translates into fraud at the polls, even though that may be beside the point.
"The allegations alone certainly wouldn't be a basis for overturning an election, but I think they prepare the public for an aggressive kind of litigation strategy," he said.
Republicans continue to mount the pressure, with their presidential nominee at the helm. McCain himself has called for an investigation into ACORN's voter registration program, and Nevada authorities last week raided ACORN's Las Vegas office after the group submitted registrations for the starting lineup of the Dallas Cowboys.
But ACORN officials defended their efforts, saying they're the ones pointing out problem registrations submitted by their canvassers, whom they pay by the hour, not by the registration. They also said they're required by law to turn in every form they collect, even if it's signed by Donald Duck.
ACORN spokesman Brian Kettenring said that although he knows the registration drives are far from perfect, "there is absolutely no doubt in our mind that the attention being paid by the right at this time is tremendously disproportionate to the problem and is distracting from a litany of other issues."
He and other voter advocates said the Republican attacks are all the more striking because allegations of widespread voter fraud have been repeatedly discredited. Most recently, in a report on the firings of U.S. attorneys accused of failing to pursue voter fraud cases, the Justice Department's inspector general found that such cases were generally dropped for lack of evidence.
Republicans denied that they're only trying to lay the groundwork for a legal challenge, and they said that registration fraud is a serious threat.
"It very well could result in unqualified people voting. It could also result in people voting more than once," said former New Hampshire Sen. Warren Rudman, who co-chairs the McCain election committee with Danforth. "And most importantly, because of the clog of paperwork of some of these registrations, it could deny election officials the time they need to get their registration lists in order."
Rudman said that such an overload of paperwork might block legitimate voters from voting. He and Danforth said they would like to work with Barack Obama's campaign to monitor polls on Election Day for irregularities.
But Obama campaign officials said they'd prefer Republicans to clean up their own act. They said Republicans are the ones trying to prevent legitimate voters from going to the polls by scaring them, pointing to an incident last week in Greene County, Ohio, where a sheriff sought the records of 302 people who had registered and voted early, because he said he was worried about possible fraud. Democrats called it a fishing expedition directed at newly registered college students. The sheriff later dropped his request.