(CNN) — The chairman of the House Judiciary Committee said Wednesday the US is in a “constitutional crisis” over a showdown about the release of a full version of special counsel Robert Mueller’s report.

“The phrase constitutional crisis has been overused, but certainly,” Rep. Jerry Nadler, D-New York, told CNN’s Alisyn Camerota on “New Day.” “Certainly, it’s a constitutional crisis, although I don’t like to use that phrase because it’s been used for far less dangerous situations.”

He added, “We are in one because the President is disobeying the law, is refusing all information to Congress.”

Nadler also told Camerota that he’s “less confident” Mueller will testify before the House after President Donald Trump publicly stated his belief over the weekend that the special counsel shouldn’t appear.

Nadler’s committee is poised to hold a vote Wednesday to hold Attorney General William Barr in contempt of Congress in the face of a threat from the Justice Department that Trump will declare executive privilege over an unredacted version of the Mueller report and its underlying evidence.

Following a day’s worth of negotiations and offers traded between committee staff and Justice Department officials, the department late Tuesday threatened to ask Trump to invoke executive privilege over the unredacted Mueller report and evidence if the contempt vote moves forward.

Nadler responded by saying the vote would still move forward, accusing the Justice Department of a “last-minute outburst” and urging negotiations over the Mueller report to continue.

The decision to hold Barr in contempt signifies the anger simmering from Democrats over what they see as across-the-board stonewalling of their oversight of the Trump administration. They have had subpoenas blocked by the administration, witnesses decline to testify, lawsuits filed by the President to block their subpoenas and earlier this week the Treasury Department rejected a request for the President’s tax returns.

Nadler also said on “New Day” that although he expects Mueller to appear before his committee, he’s “less confident” that will happen. On Sunday, Trump, who had previously deferred to Barr on whether Mueller should provide congressional testimony, reversed course and publicly said Mueller shouldn’t appear before the Judiciary Committee.

“Well, now that the President has said what he said, I’m less confident than I was,” Nadler told Camerota.

Nadler said he thinks Trump will attempt to stop Mueller from testifying, but added that “whether he’ll succeed is another question.”

The Judiciary chairman doesn’t think the President will have “any legal way” to prevent Mueller, who is still a Justice Department employee, from appearing before the panel once he becomes a private citizen.

Judiciary Committee member David Cicilline, a Rhode Island Democrat, told “Fox News Sunday” that the committee has reached a “tentative date” of May 15 for Mueller to testify, though he later clarified that the date for Mueller’s appearance had not yet been finalized.