Transcript for Trump calls news Robert Mueller will testify on Capitol Hill 'a disgrace'
Next tonight, Robert Mueller will testify before congress after all, and tonight, our Terry Moran asking president trump, will he try to stop Mueller? What we've learned. Terry reporting in from the white house tonight. Reporter: President trump, irate at the news that Robert Mueller will testify before congress. It's a disgrace. No obstruction, no collusion. Now the Democrats want a do-over. Reporter: House judiciary committee chairman Jerry Nadler defending his decision to subpoena the special council. It's very important that the American people hear from Mr. Mueller. Reporter: A key issue, will Mueller explain his cryptic statement about whether the president obstructed justice? If we had had confidence that the president clearly did not commit a crime, we would have said so. Reporter: Republicans are bracing for a fight and questioning Mueller's motives. It looks awfully political. In his decision to make a statement last time was a smart thing to do, to just go in front of the American people and say, I've done the best I can, here's my report, I trust the American people to read it and draw their own conclusions. End of story, bye. Reporter: President trump has stonewalled house Democrats, asserting executive privilege and blocking their subpoenas of his aides and former aides. Will you try to block Robert Mueller from testifying? I don't know anything about it, I just heard. And my only response to Mueller is, does it ever stop? Reporter: Later today, the president's lead lawyer tried to clarify that answer, saying there are no legal moves being made to block Mueller from testifying. That's the president's lawyer, David. The president, of course, makes the final call. Terry Moran live at the white house tonight. Terry, thank you.
This transcript has been automatically generated and may not be 100% accurate.