WASHINGTON (AP) — The Democratic National Committee on Friday filed a complaint with the Federal Elections Commission, accusing presidential candidate Robert Kennedy Jr. of a “ballot access scheme” that it argues constitutes illegal coordination with a super PAC supporting his independent bid for the White House.

The committee alleges that the Super PAC American Values 2024 is working to collect signatures to ensure Kennedy is on the November ballot in key states, but will have to “integrate their expenses” with the campaign in ways that violate federal election rules in order to do so.

That’s because, the DNC argues, many states — including Arizona, Illinois and Michigan — have rules that candidates or their campaigns be the ones collecting ballot signatures, meaning Kennedy’s campaign will have to violate federal rules to meet state requirements.

“They simply cannot comply with federal law and state law at the same time,” DNC legal counsel Bob Lenhard said on a conference call with reporters.

Tim Mellon, a major donor to Donald Trump, gave American Values $15 million last year, according to federal filings. The DNC alleges that those donations suggest that top supporters of the former president are using Kennedy’s candidacy to try and siphon support from President Joe Biden ‘s reelection bid.

On the call with reporters, the DNC argued that “Trump and his megadonors are propping up RFK Jr. as a stocking horse.”

The complaint comes amid increasingly Democratic worry about third-party candidates potentially siphoning support away from Biden. Kennedy began his White House campaign last year as a challenger to Biden in the Democratic primary only to later switch to a third-party bid, though, meaning he could also draw some would-be Trump supporters.

Kennedy’s campaign didn’t respond to requests for comment, but American Values said it has been working independently from the campaign to get him on the ballot in 12 states and dismissed the DNC complaint as “political games.”

“The DNC wants to deny millions of people their basic constitutional voting rights in a relentless onslaught against democracy,” Tony Lyons, the group’s co-founder, said in a statement. It added that “the Biden administration and the DNC clearly find democracy inconvenient, want to stifle any dissenting opinions and don’t believe that their candidate can win a free, open and fair election.”

Filing complaints with the FEC for improper coordination with campaigns isn’t uncommon. In December, a campaign watchdog group filed a complaint alleging that Never Back Down, a super PAC supporting Republican Ron DeSantis, was coordinating too closely with the Florida governor’s since-suspended presidential campaign.

But Linhart said the DNC took the unusual step of filing a complaint against Kennedy itself because what was occurring was “striking” and “dramatic” given that some states mandate candidates or their campaigns collect ballot signatures.

“The state law element adds an extra level of legal concern,” Linhart said.

More about: