U.S. District Judge Tanya Chutkan on Wednesday ordered former President Donald Trump to formally declare whether he plans to argue that he was acting on the advice of his lawyers in his D.C. election subversion case.

Chutkan partially granted a motion from special counsel Jack Smith’s team asking her to require Trump to declare whether he plans to use the advice-of-counsel defense, in which a defendant argues that he relied in good faith on the advice of his attorneys.

Smith in a filing last month noted that several Trump lawyers have said in media interviews that Trump was acting on the advice of his lawyers.

“When a defendant invokes such a defense in court,” Smith’s office argued, “he waives attorney-client privilege for all communications concerning that defense, and the government is entitled to additional discovery and may conduct further investigation, both of which may require further litigation and briefing.”

Chutkan in her order on Wednesday wrote that while federal rules “do not expressly require advance notice of the advice-of-counsel defense” but “because waiting until trial to invoke the defense—and comply with the disclosure obligations it triggers—could cause disruption and delay, some district courts have concluded that they nonetheless have inherent authority to order defendants to provide advance notice if they intend to do assert the defense.”

Chutkan gave Trump until January 15 to disclose whether he plans to use the defense after Smith’s team requested notification by December 18.

Former U.S. Attorney Barb McQuade called the order “big and appropriate.”

“If Trump plans to use advice of counsel defense at trial in election interference case, he waives attorney-client privilege and must turn over documents to prosecution. He can’t have it both ways,” she wrote on X/Twitter.

The judge’s order “puts Trump in a box on one of his main defenses,” tweeted CNN legal analyst Norm Eisen.

“She’s requiring that he disclose private communications” with the attorneys, Eisen explained, “or else he can’t advance the defense. No good choice for him here.”

The order means “Trump has to put up or shut up on this well in advance,” wrote former U.S. Attorney Harry Litman.

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“He doesn’t have the legal basis for asserting advice of counsel— and he’d have to waive privilege—so getting it out in the open early will preempt them from pulling fast ones,” he added.

Former U.S. Attorney Joyce Vance predicted that Trump will have a “heavy lift convincing the judge to permit him to use an advice of counsel defense at trial.”

“Among other things, because you can’t rely on the advice of your co-conspirators, even if they’re lawyers,” she wrote. “If the Judge rules against him, it can’t be mentioned at trial.”