A Chicago federal trial judge is weighing competing claims concerning whether he has the power to move forward with a civil contempt investigation that could punish a U.S. regulatory agency for allegedly making public statements outside the bounds of a $16 million settlement with two major food manufacturers.

Defense lawyers at Jenner & Block and Eversheds Sutherland, representing Kraft Foods Group Inc. and Mondelēz Global LLC, late Monday asked U.S. District Judge John Robert Blakey of the Northern District of Illinois to hear arguments that the U.S. Commodity Futures Trading Commission should be held in contempt for allegedly violating the terms of the settlement.

The CFTC, meanwhile, contends that any contempt proceeding is no longer an option after the judge vacated the underlying settlement. Blakey, who had earlier approved the settlement, recently erased the agreement amid claims from Kraft and Mondelēz that the CFTC and its leaders violated a provision that restricted what the parties could tell the public about the deal.

Contempt proceedings involving federal agencies are rare, and the action in Chicago is being closely watched among white-collar and compliance lawyers. The law firm Kobre & Kim earlier this month sued the CFTC in New York federal court to force the disclosure of documents tied to the settlement and its gag provision.

Blakey, at the request of Kraft and Mondelēz, in August initiated civil contempt proceedings against CFTC leaders, including Senate-confirmed commissioners, over public statements about the agency's settlement. A federal appeals court this month stopped any contempt investigation of CFTC officials, but the panel allowed the trial court to consider whether to reprimand the agency itself.

CFTC lawyers and outside counsel—commissioners hired a King & Spalding team to represent them individually—have argued the agency and its leaders did not violate the terms of the settlement with Kraft and Mondelēz. Nothing in the settlement prohibited commissioners from speaking about the deal, and statements from the CFTC itself generally addressed enforcement priorities, the CFTC has argued.

Jenner partner Dean Panos, leading the push to hold the CFTC in contempt, has said the "CFTC and its commissioners engaged in a deliberate, orchestrated effort to violate the court's consent order within minutes of its entry." The CFTC subsequently removed three press statements from the agency's website while the contempt dispute has unfolded.

Lawyers for the CFTC assert Blakey has no power to punish the agency and should dismiss the contempt motion as moot. The judge's underlying settlement order is "no longer in effect," CFTC general counsel Daniel Davis said in a court filing Nov. 8.

On Monday, Panos argued that Blakey still has authority to hold the CFTC in contempt despite the fact the judge voided the settlement and effectively ordered the parties to start from scratch.

"The CFTC must follow lawful orders of this court and may not benefit from its intentional violation of those orders, or its misconduct in inducing their issuance. When the CFTC violates orders of this court, as it has here, it should be held responsible," Panos wrote.

In the court filing, Panos said the CFTC's action had "real consequences." The public statements the CFTC made about the Mondelēz and Kraft settlement, he said, "cannot be un-made." He added: "Second, with the reinstatement of the lawsuit, defendants' potential exposure is no longer capped at $16 million as it was under the settlement, and defendants must incur legal fees in this case, potentially through trial."

Lawyers for Mondelēz and Kraft argued in their filing that "the CFTC should not be allowed to benefit from its wrongdoing, and this court is empowered to do something about it."

The defense attorneys said Blakey has at least several options he can consider as possible punishment, including entering a contempt finding and rebuking the CFTC, capping any potential liability at $16 million and awarding legal fees. "Defendants now must likely spend millions of dollars more in legal and expert fees and face uncertain liability," Panos asserted in the filing.