On Monday night, the Mississippi
But earlier in the day, more than 200 McDaniel supporters arrived at courthouses in the state's 80 counties to scour voter logs for irregularities. The campaign has offered 15 $1,000 rewards for information leading to voter fraud convictions.
"We're surprised at the amount of evidence that continues to come forward that shows us that there has indeed been election fraud in this case," Mitchell Tyner Sr., a Mississippi trial attorney and lead counsel for the McDaniel campaign, said at a news conference at the county courthouse in Jackson. "We do not want to see any election decided by ineligible voters."
Though McDaniel supporters are livid that Democratic votes for Cochran may have cost McDaniel the Republican nomination, nothing in Mississippi law prevents voters from crossing party lines to cast ballots in primary elections.
However, Mississippi law does prohibit voters who already cast a Democratic ballot in the June 3 primary from participating in the Republican runoff. That's now the apparent legal basis for McDaniel's challenge.
As they seek to make their case for a do-over election, McDaniel's supporters have suggested as many as 5,000 votes could be fraudulent. Cochran's team dismisses that assertion, and said Monday the results of the canvassing so far have revealed "an extremely low number of crossover votes."
"As we have said from the beginning, the runoff results are clear: the majority of Mississippians voted for Sen. Thad Cochran," spokesman Jordan Russell said. "As the process moves forward, the conversation is shifting from wild, baseless accusations to hard facts."
Cochran's campaign made no secret that it was reaching out to Democratic voters, including African Americans, in a strategy to expand the electorate after the six-term senator failed to win first-round voting against his firebrand challenger.
Voter participation typically drops off for runoff elections, but an additional 70,000 voters turned out during the second round. The race found a national audience when tea party conservatives targeted Mississippi as their best chance to knock off a Republican incumbent they viewed as insufficiently conservative.
A series of bizarre episodes, including the arrest of a blogger who posted an unauthorized photo of Cochran's ailing wife in her nursing home, have punctuated the race. Another tea party official in Mississippi accused of participating in the photo incident died in an apparent suicide last month.
Separately, a lawsuit was filed last week by True the Vote, a Texas-based voter integrity group, on behalf of about a dozen Mississippi voters, also raising questions about the crossover voting.
Unlike in many states, Mississippi's secretary of state office plays a modest role in elections. Instead, the political parties certify the county results.
With Monday's GOP certification, state law now allows a legal challenge, which McDaniel's team is expected to file this week. After 10 days, the challenge may also be filed in court.
Mississippi has a long history of voter suppression culminating in the civil rights battles of the 1960s, but rarely, if ever, in modern politics has a statewide legal challenge been posed on this scale, observers said.
"This is a unique sort of challenge, and it's not one I have encountered on a statewide level of 35 years of covering politics," said Sid Salter, a longtime journalist in the state who is now the director of public affairs at Mississippi State University.
Republicans worry that the prolonged primary battle could help Democratic candidate
So far Childers has quietly continued his own campaign, trying to avoid interrupting what has become another Republican slugfest.