Washington (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.