Now, early voting is being added the list of possible suspect actions.
Speaking to Sean Hannity on his radio show on Wednesday, former GOP presidential candidate Rick Santorum claimed that letting citizens cast ballots in person before Election Day opens the door to corruption:
Hannity: I don't like this early voting --
Santorum: I hate it.
Hannity: It's been going on forever --
Santorum: I hate it.
Hannity: And it opens up the door to corruption.
Santorum: It does. And look, the race changed from a month ago. When Ohio was early voting, it was before the first debate and the people who went out and voted, really in my opinion, really didn't know Governor Romney and what kind of candidate he really is and the real distinction between Romney and Obama.
Santorum did not elaborate on how casting a ballot before, rather than on, Election Day could lead to corruption. A Santorum media representative did not respond to a request for comment.
Dan Tokaji, an election law expert and law professor at The Ohio State University, had only two words to say in response to Santorum's corruption claim: "completely bogus."
Rick Hasen, a University of California-Irvine law professor who also studies elections and voting regulations, was similarly skeptical.
Early voting in swing states like Ohio and Florida requires citizens to come to voting stations in order to cast their ballots. In-person voter fraud is exceedingly rare, Hasen told HuffPost.
When doing research for his book, The Voting Wars, Hasen attempted to find a single credible case of in-person voter fraud within the last generation and turned up empty-handed, he wrote in an article for The New York Times.
Instead, Republicans continue to stress the threat of voter fraud to secure a political advantage, Hasen argued.
"As this country has been polarized in the last decade since Bush v. Gore and the Florida debacle, the Republicans have pushed hard the line that there is a lot of voter fraud in elections and fraud committed in particular by Democrats," Hasen told HuffPost. "And these claims are used to pass various laws like voter ID laws, but also to get the base excited -- 'Come out and vote so that Democrats don't steal the election.'"
Tokaji noted that fraud is much more prevalent among votes cast by mail, including absentee ballots submitted by mail.
"Why don't you see the same statements being made about absentee, mail-in voting?" Tokaji said. "If you look at the population that predominantly uses it -- they're Republican."
The Romney campaign has made a concerted effort to check that states sent out absentee ballots to members of the military serving abroad at least 45 days before the election, as required by law.
Early in-person voting, on the other hand, played a hand in tipping the scales for President Barack Obama in 2008 in key swing states like North Carolina. In recent years, early-voting has been popular with African-American and other minority voters.
Tokaji said he believes that that high Democratic turnout has led Republicans to start attacking the process. In 2012, Republican-led state legislatures in both Florida and Ohio tried to limit the number of early voting hours.
In Ohio, the struggle over early voting has made it as far as the Supreme Court. Secretary of State Jon Husted (R) announced that, unlike in 2008, early voting would be available only to military voters on the Saturday, Sunday and Monday before Election Day. The Obama campaign sued, asking the courts to mandate that every Ohio voter be able to cast a ballot that weekend.
"At the time that the Obama campaign brought this legislation, they got a lot of flack from people on the right especially, who alleged that the Obama campaign was seeking to take early voting rights away from military personnel," Tokaji told HuffPost. "That was not in fact true. What the campaign was asking for -- and ultimately got -- was an order that brings everyone up to the same level when it comes to early voting. It doesn't take away anyone's rights."
Husted and his legal team complained of the burden imposed by keeping early voting stations open that weekend.
A Republican election official in Ohio offered a different rationale. Doug Preisse, who also serves as the chair for the Franklin County GOP, voted against extending early voting in his county.
"I guess I really actually feel we shouldn’t contort the voting process to accommodate the urban -- read African-American -- voter-turnout machine," Preisse said, explaining his vote to The Columbus-Dispatch in an email. "Let’s be fair and reasonable."
When doing his research, Hasen said several county officials told him that early voting made it easier on them on Election Day.
"Elections are always a burden for election officials," Hasen said, "but they are worth being burdened with."
On Oct. 16, the Supreme Court decided against hearing Husted's case, which means all Ohioans will be able to cast ballots in the three days prior to the election.
In the 2012 election, members of both parties have focused on taking advantage of early voting. Republican National Committee Chair Reince Priebus has been going from state to state -- most recently in Wisconsin and Virginia -- urging people to get out to the polls early, so they can spend Election Day helping others turn out.
While visiting a campaign office in Arlington, Va. on Thursday, Priebus said that early voting means campaigns need to adopt a different strategy than what would be used in a state like Pennsylvania.
"[You have to] go after low-propensity voters," Priebus said. "For instance, if you're a voter who votes in every single election, every primary, every school board election, we know you're a GOP voter, we are probably not going to take one of these volunteers to knock on your door ... because we know you're going to vote."
Hasen highlighted that there certainly are potential drawbacks to the early voting process. As Santorum pointed out, early voters could cast their ballots before they know all of the important facts about a candidate.
"When you have something like what happened with [Senate candidate Richard] Mourdock (R-Ind.), Hasen said, people would probably have wanted to know that [before voting]."