McDaniel said he did not recall voting in a Democratic primary.
"I have never voted in a Democratic primary," McDaniel told the Mississippi newspaper. "I've only missed a couple of votes in my life, like when I had the flu … that's just people being desperate and tacky. I don't remember voting ever in a Democratic primary … I was absolutely voting in the Republican primary. I remember Haley (Barbour) was running for governor against a lawyer in Jackson."
McDaniel's campaign spokesman, Keith Plunkett, later told the Clarion-Ledger that there's a chance the state senator and tea party challenger could have voted in the Democratic primary in 2003. But in an email to TPM on Wednesday Plunkett confirmed that McDaniel did, in fact, vote as a Democrat in 2003.
"Over a decade ago, Chris McDaniel voted in a Democratic primary in order to have a choice in local competitive elections," Plunkett told TPM. "However, as the attacks from Democratic politicians have made clear, McDaniel's conservative Republican record in the Senate speaks for itself."
This is the latest bump in the road for McDaniel since he announced his candidacy for Cochran's seat. It was previously revealed that McDaniel attended at least one neo-confederate event in Mississippi.
This post has been updated.