JACKSON, Mississippi — Sen. Thad Cochran (R-MS) is appealing to Democratic voters to cross party lines and vote in an upcoming runoff election against his conservative challenger, state senator Chris McDaniel. But a noted election law expert says that may be illegal.

J. Christian Adams, a former Civil Rights Division attorney at the Department of Justice with experience litigating election law cases in Mississippi, said a law there prevents people from voting in the primary for candidates they don’t plan to support in the general election.

Adams is now a high-profile author and news commentator for conservative outlet PJ Media. He resigned his position at the U.S. Department of Justice in 2010 over how the Obama administration treated a famous case against the New Black Panther Party for alleged voter intimidation at the polls in Philadelphia, Pennsylvania. 

The Mississippi law Adams cites, MS Code 23-15-575, states: “No person shall be eligible to participate in any primary election unless he intends to support the nominations made in which he participates.”

“Mississippi law prohibits Democrats from voting in a Republican primary,” Adams said in an emailed statement. “Obviously poll workers aren’t mind readers. But if someone doesn’t intend to support the nominee in November, then that person isn’t allowed to vote in the Republican primary.”

In addition, the state Democratic Party sued Gov. Haley Barbour and others in the mid-2000s regarding just that matter–prompting United States District Judge W. Allen Pepper to write in a June 8, 2007, opinion that it is the responsibility and right of the political party holding a primary election to ensure that the elections are fair and legal. In the case of a Republican primary and runoff, only Republicans vote, and in the case of a Democrat primary and runoff, only Democrats vote–and it is the role of the political parties to ensure that process is handled correctly.

The Supreme Court determined in a 2005 case that the First Amendment “protects the right of political parties to associate with fellow members and disassociate with non-members,” Judge Pepper wrote in his opinion. So technically it’s the party’s responsibility–i.e., in this case, state GOP chairman Joe Nosef’s responsibility–to protect GOP voters’ First Amendment rights by working to keep Democrats from voting in the GOP primary runoff.

Catherine Engelbrecht, the head of national conservative election integrity organization True the Vote, told Breitbart News she thinks Nosef must step up and enforce these laws. Engelbrecht and her organization are in Mississippi right now, preparing for the election with poll watchers from around the country to work to prevent any shenanigans on election day next week.

“Chairman Nosef must understand that this matter is not playing out in an echo chamber; people across the country are now suspicious about what they see happening in Mississippi,” Engelbrecht said in an emailed statement. “Breaking this law or any other voter integrity law – erodes America’s confidence in our elections. With only a handful of days remaining until the runoff, it is Chairman Nosef’s responsibility to enforce the rule of law and restore our trust.”

Nosef hasn’t responded to a request for comment on the matter from Breitbart News. 

A group of conservative state senators who support Cochran’s primary challenger, state Sen. Chris McDaniel, are demanding that Nosef intervene to keep this practice from happening.

The group of state senators rallying him highlights McDaniel’s bench of local power brokers fighting from the ground up against Cochran’s political establishment team fighting from the top down in this election. It’s been a common theme in this Mississippi primary: McDaniel’s power comes from grassroots activists and local lawmakers throughout the state, whereas Cochran’s comes from hubs in Jackson, MS, and Washington, D.C. While the state senator team backing McDaniel is constantly appearing alongside him throughout the state at campaign rallies, the group rarely unites to push a message like it is now.

Their calls come largely in response to reports Tuesday from allegations by Mississippi Democratic Party chairman Rickey Cole that a super PAC backing Cochran is routing money to Democratic operatives for get out the vote activities.

Cole said noted Democratic operative James “Scooby Doo” Warren, who confirmed to the Clarion-Ledger newspaper he is working for Cochran, is known for paying individuals to vote and providing “walking around money” to volunteers. Warren has not publicly addressed the allegations, and Pete Perry, the Cochran ally and Hinds County GOP Chairman whom the super PAC money was routed through, said he hopes that such activities aren’t occuring.

Sen. Philip Gandy of Waynesboro told Breitbart News he’s equally “deeply disturbed” to hear “allegations of funds being funneled to encourage Democrats to vote in the June 24 Republican primary runoff,” and called for the state Republican Party to launch an investigation.

“It is shameful that some in the Republican party would stoop to such a level of courting the Democrat vote in a Republican primary,” Gandy said. “I call on the Republican party to get involved and to get to the bottom of these allegations.”

State Sen. Angela Hill of Picayune cited the same law Adams did in her comment to Breitbart News, saying that Cochran’s supporters “should read” that law. 

“A responsible party should investigate these allegations,” Hill said, adding that she thinks this reflects poorly on the state GOP.

“The Republican Party has never been the food stamp party, or the party of pork until desperation set in with Thad Cochran’s re-election bid,” Hill said. “I have never seen such open collaboration to get Democrats to spoil a Republican party primary or runoff as is being openly displayed by Thad Cochran operatives in the MS GOP establishment.” 

“Many have worked for years to build the Republican Party and sent their checks to an organization who has pledged to support the Republican ideals of limited government, free markets, self-reliance, and fiscal responsibility, so it is sad to see the party leadership across the state reach out to Democrats in an organized fashion to try to keep a proven conservative out of Washington,” she continued. “This begs the question ‘What does the MS GOP establishment really stand for?'”

Sen. Michael Watson of Pascagoula added that these efforts could harm the electoral prospects of all other Republicans in future elections.

“I trust the state party apparatus is doing its job and working to protect the integrity of the primary process,” Watson told Breitbart News. “At a minimum, it seems there should be an investigation into some of the allegations. If there’s not, I foresee a real problem for them with the base of the party in next year’s election cycle.”

State Sen. Tony Smith of Picayune called on the U.S. Attorney’s office to investigate the matter.

“I am very troubled to learn of the tactics being used in an attempt to sway the outcome of the Republican primary,” Sen. Tony Smith of Picayune told Breitbart News. “To buy votes or influence from those who have no intentions to vote for the republican nominee in November is absurd. I ask that US Attorney Greg Davis investigate these allegations as quickly as possible.”

The U.S. Attorney’s office in Jackson has not responded to a request for comment on the matter.