As part of an escalating feud with the Democratic National Committee, longshot presidential hopeful Martin O’Malley on Tuesday released a memo from a campaign lawyer calling the party’s debate plan “legally problematic.”

O’Malley, the former Maryland governor, has strongly objected to the schedule released last week of six DNC-sanctioned debates, branding it “undemocratic” and arguing that the public deserves more opportunities to size up frontrunner Hillary Rodham Clinton against other candidates.

The memo released Tuesday takes issue with an “exclusivity” requirement, under which any Democratic candidate who participates in a non-sanctioned debate could be barred from the DNC-sponsored debates, the first of which is in October.

Joe Sandler, a former DNC general counsel whose services have been retained by O’Malley’s campaign, argues in the memo that such a requirement is unprecedented and that the DNC has no legal authority to enforce it. The memo was first reported by MSNBC.

The debates are being sponsored by 10 media outlets and one nonprofit group, and under Federal Election Commission rules, it is up to the sponsors of each debate to decide who appears on stage, Sandler writes. “Legally, the DNC cannot dictate the format or structure of any debate … including the criteria for participation,” he says.

Holly Shulman, the DNC’s national press secretary, said the DNC and the media outlets have agreed to the participation criteria, and she repeated the party’s view that “six debates will give plenty of opportunity to be seen side by side.”

Sandler, however, argues that such an arrangement is “legally problematic” because none of the debate sponsors can be bound by the DNC or other debate sponsors.

O’Malley, who is trailing both Clinton and Sen. Bernie Sanders (I-Vt.) in the polls, clearly has an incentive to share a stage with them as often as possible. During his campaigns for governor, O’Malley proved an able debater, and as a presidential hopeful, he is eager for more attention.

Sanders has also called for more debates, while Clinton demurred this week when asked by reporters in New Hampshire if she’d like to see additional encounters.

Traditionally in politics, candidates who are trailing tend to be far more interested in debating that those leading in the polls. For O’Malley, the shoe has been on the other foot in the past.

During his first bid for governor in 2006, O’Malley’s Democratic primary opponent, Douglas M. Duncan, needled O’Malley for months, claiming he wouldn’t debate him enough at a time when O’Malley was leading in the polls. At one point, Duncan staged an event with a cardboard cutout of O’Malley to try to drive home his point.