The Judiciary Committee is set to hear Wednesday from four constitutional scholars who are expected to testify on the standards for impeachment — three chosen by Democrats, one by Republicans. Rep. Jerrold Nadler (D-N.Y.), the panel’s chairman, has not yet named the witnesses, prompting protests from Collins, despite the matter being handled in accordance with House rules.

Some Republicans on Sunday predicted that the impeachment inquiry will take a turn for the combative once it reaches Nadler’s committee.

“It’s a bunch of brawlers sometimes on the Judiciary Committee, so it should get pretty hot and under the collar as we go along,” Rep. Andy Biggs (R-Ariz.), who sits on the panel, said in an interview with Fox News Channel’s Mike Emanuel on “Sunday Morning Futures.” “I don’t think things have been done the way they’ve been done in the past, Mike, and so it causes some rancor and it should be pretty — much more feisty, I would say, than the Intel Committee was.”