A progressive watchdog group filed a complaint with the Federal Elections Commission arguing that Rep. Dean Phillips' (D-Minn.) presidential campaign illegally coordinated with a supporting super PAC, according to a copy of the complaint obtained by Axios.

Why it matters: The complaint filed by Campaign for Accountability on Tuesday night is the latest headache for Phillips, who made a late entry into the Democratic primary in October to challenge President Biden.

Driving the news: The complaint signed by the group's executive director Michelle Kuppersmith argues that "there could scarcely be a more blatant and egregious example of a presidential campaign illegally coordinating with a super PAC."

• Steve Schmidt, a prominent former Republican consultant, was deeply involved in the launch of Phillips' campaign, including traveling with him when he entered the New Hampshire primary.
• Schmidt then left the campaign to form a super PAC called Pass the Torch, while Phillips hired former Bernie Sanders campaign manager Jeff Weaver to take the helm of the campaign.
• Given that Schmidt helped launch the Phillips campaign and the super PAC echoed its messaging in an ad, Campaign for Accountability argues that Phillips likely violated the Federal Election Campaign Act and FEC guidelines.

What they're saying: "The complaint is baseless and does not allege a single specific example of coordination. All it takes is one look at our paid TV ads to see how different the strategies of these two entities are," the Phillips campaign told Axios.

• Asked if the campaign ever paid Schmidt before he left for the super PAC, the campaign said: "We can say without question that the campaign has at all times complied with the law and has not engaged in any coordination with Pass the Torch, Steve Schmidt, or any other party."
• In response, Kuppersmith told Axios: "Steve Schmidt by his own admission helped develop the messaging for the Phillips campaign and then he helped launch a Super PAC. All these parties can say all they want that the messaging strategies diverged, but it appears plainly obvious to us that this was an arrangement that started from coordination and we think the FEC will agree with us."
• Schmidt did not respond to a text message. Pass the Torch did not respond to a request for comment.

Zoom in: Saurav Ghosh, director of federal campaign finance reform at Campaign Legal Center, said that Phillips' campaign is worth investigating further — but that the rules aren't clear cut.

• Ghosh told Axios: "Can an unpaid senior adviser for a campaign depart and start a super PAC? Legally, they can."
• "But it would be legally problematic if Schmidt served as a top adviser —either paid or unpaid — to a presidential candidate, helped inform campaign strategy and then left to start a super PAC, because he could use his knowledge of the campaign's strategy to guide the super PAC's spending," Ghosh added.

Zoom out: Phillips has bet much of his campaign on earning a better-than-expected showing in the New Hampshire primary on Jan. 23, where Biden will not be on the ballot and must rely on write-in votes.

• The Democratic Party has so far successfully blocked Phillips from getting on the ballot in other states like Florida and North Carolina.
• Phillips has focused much of his campaign on electability and Biden's vulnerability against Donald Trump in a general election, as recent polls have shown.
• A USA Today/Suffolk University poll last week found Biden dominant nationally with 74% support compared to Phillips' 2%.