Transcript for House Democrats issue a subpoena to the White House
We have a ton of great story, hilarious surprises all in store coming up soon but want to start with the fast-moving developments in the impeachment Here's what we know. A major escalation from house Democrats issuing a subpoena to the white house for documents related to Donald Trump's July phone call with the leader of Ukraine. After the administration missed a previous deadline to hand over material. Joe Biden taking questions from reporters for the first time since the story began and "The New York Times" reporting there may be a second whistle-blower preparing to come forward. We have team coverage and we begin with ABC's David Wright at the white house. David, good morning. Reporter: Good morning, guys. This is a fast-moving story. The Democrats on capitol hill turning up the heat after the white house ignored a deadline to hand over documents voluntarily, house investigators, issued subpoenas compelling them to do so. It's a significant escalation but the committee chairs say that the president left them with no choice. Citing what Democrats describe as the president's flagrant disregard for their repeated requests for documents, the house oversight committee sent the white house a strongly worded letter, noting that any further delay shall constitute evidence of obstruction. We've been treated very unfairly. Reporter: The white house issued a statement saying the subpoena changes nothing and is a waste of time and taxpayer dollars. President trump Friday continued to slam former vice president Biden. What I want to do and I think I have an obligation to do it, and probably a duty to do it, corruption. We are looking for corruption. When you look at what Biden and his son did and when you look at other people. Reporter: Biden hit back. We got to get something straight. All of this talk from the president about corruptionomes from the most corrupt president we've had in modern history. Reporter: The congressional investigation as to whether he sought to strong arm a former police department rival into digging up dirt on a political rival is expanding rapidly. House speaker Nancy Pelosi told Democrats -- This is something that treated with great care, there may be some in this room thought we should have been sooner. I just said when we have more facts, we will be ready. Reporter: Among Republicans, senators Ben sasse and Mitt Romney remain the only Republicans in the senate to break ranks with the president. Romney calling the president's behavior, wrong and appalling. Compare that to senator Marco Rubio. Do you think it's okay for president trump to ask China to launch an investigation of Joe Biden and hunter Biden? I don't know if that's a real request or him just needling the press knowing you guys would get outraged by it. Reporter: Back in their districts. Where is the line? When are you guys going to say enough? Reporter: Others find themselves on the defensive. "The Washington post" filmed this cons Stitt constituent confronting senator Joni Ernst over her refusal to criticize president trump. I can't speak for him. I'll just say that. I can't speak for him. I know you can't speak for him but you can speak for yourself. Reporter: This morning "The New York Times" reports there may be a second possible whistle-blower, an intelligence official already interviewed by the inspector general. According to the "Times," this person has more direct knowledge of president trump's dealings with Ukraine and is now weighing whether to file a complaint of their own. Eva. All right, David, thank you.
This transcript has been automatically generated and may not be 100% accurate.