Transcript for Debate over impeachment heats up after Mueller report
Thank you. We'll stay in Washington for the debate over impeachment. The 2020 candidates took the stage in town halls in new Hampshire. Jon Karl has the story. Good morning, Jon. Facing intense pressure to begin impeachment proceedings in the house Nancy Pelosi convened an extraordinary conference call with house Democrats yesterday. She heard from many who want that impeachment process to start now. But she made it clear she wants to hold off at least for now. As speaker of the house Nancy Pelosi faces intense pressure from fellow house members to begin impeachment proceedings, some of the most high-profile democratic presidential candidates are now piling on too. To illustrate how strongly she feels about impeaching Donald Trump Elizabeth Warren brought up a new rally cry. Lock him up. If any other human being in this country has done what's documented in the Mueller report they would be arrested and put in jail. Reporter: Warren was the first major democratic presidential candidate to respond to the Mueller report by calling for impeachment. During a series of CNN town hall meetings last night senator kamala Harris said she too wants impeachment hearings. I believe congress should take the steps towards impeachment. Reporter: That puts Warren and Harris at odds with Pelosi who is preaching caution. We showed proceed down a path of finding the truth Pelosi wrote, it is also important to know that the facts regarding holding the president accountable can be gained outside of impeachment hearings. Warren rejected Pelosi's call for caution. There is no political inconvenience exception to the United States constitution. Reporter: But not all democratic presidential candidates are on the impeachment bandwagon. All that the congress is talking about is impeaching trump and trump, trump, trump and Mueller, Mueller, Mueller. What I worry about is that works to trump's advantage. There is a third way to hold this president accountable and that is by defeating him in the 2020 election and I believe I can do that. I think he's made it clear he deserves impeachment. I'll leave that to them to figure out. Reporter: Regardless president trump insists he's not concerned in the least. Are you worried about impeachment, Mr. President? Not even a little bit. Reporter: I'm told Pelosi's conference call lasted well over an hour, George, and was quite impassioned although she made the case for proceeding cautiously and not starting impeachment now, she also pointedly did not rule it out. What she said the house should start doing now though is go through a series of investigations outside of the impeachment process. Okay, thanks very much.
This transcript has been automatically generated and may not be 100% accurate.