Transcript for Democratic presidential candidates speak out on impeachment
David, thank you. Whit over to you. The impeachment overshadowing policy messages from Democrats on the campaign trail. I caught up with several candidates acknowledging the political risk. Reporter: On the eve of a historic week in Washington the gravity of the impeachment inquiry looming large over the campaign trail. This is about Donald Trump, not about me. Reporter: Former vice president Joe Biden defiant amid calls from president trump and Republicans for both him and his son to testify in public hearings. There's not a single solitaire scintilla of evidence anywhere that somehow I did anything wrong. What trump is doing what he always does. Take the focus off the problem. Reporter: Of the 17 Democrats running for president seven of them are currently serving in congress and could be called back to capitol hill to participate in the inquiry including senator Bernie Sanders who sat down with our Rachel Scott. I'll be doing my job when I'm there. I'll have to be in Washington, D.C. And Des Moines, Iowa and Concord, New Hampshire at the same time. I'll do my best. We'll do what we have to do. Reporter: The tone somewhat measured among most of the presidential hopefuls bracing for potential fall-out. Do you still worry that these public hearings, the inquiry is a distraction and can hurt Democrats politically? Some things come along that are so important that you have to put the political aside. I don't know what the political consequences of impeachment will be. I know what the moral and constitutional consequences would be if there were no accountability at all. Impeachment has the potential to be a real distraction. Any opportunity we have to present a new positive vision for the company, that's what we should be doing. Reporter: Democrats hoping this cuts through the noise. I'm not concerned about anything. The testimony has been fine. Despite the impeachment inquiry grabbing headlines, many candidates say when they're out there crisscrossing the country, it's not the first thing voters are bringing up. They're mostly concerned about kitchen table issues, things that impact them, health care, economy, jobs. I was at a Andrew yang rally. Not one single person asked about impeachment. It's a telling detail. So much to talk about politically this Sunday morning. Let's bring in our ringer, ABC's Martha Raddatz who is hosting "This week." Martha, good morning. Let's start with the impeachment saga that will publicly un-ferrell in Washington on Wednesday. Do you think the democratic presidential candidates are correct to wring their hands public about the fact this process could be a distraction and could impair the party's odds of retaking the white house? I think it's a distraction. It most certainly is. It's a very important event on capitol hill. There will be a lot of attention focussed on that. Indeed people won't be following the race quite as much. I loved hearing whit saying he's out there talking to people and they're not concerned about that. They want to talk about issues. You can be certain reporters will be continuing to ask those candidates about impeachment and how it's impacting the race. There's very little time before Iowa and New Hampshire. If these impeachment hearings go on and on and after the holidays, then they have to worry about refocusing their message. Of course Joe Biden is going to have to keep defending himself because president trump and Republicans keep bringing this up. And trying to get his son to testify. As we know, the Democrats will try to make this a speedy process. It's been reported that the Republicans may try to slow it down. So much going on on that front. There's a lot going on internationally on your show this morning. You'll have the first interview with the new chairman of the joint chiefs of staff S general mark Milley. You asked him about the president's controversial policy on Syria. Let's listen to that. If I do my math and look at the new troops coming in and going out, it could be more than 700 who remain. There will be less than 1,000 for sure. Probably in the 500ish frame, maybe 600. It's in that area. We're not going to go into specific numbers. We're going through the analysis right now. As I understand it, the president has said he wanted all the troops out of Syria. Are we hearing the military defy the president? I would absolutely not call it defying the president. I think general Milley, chairman Milley is giving his best military advice. It's not necessarily that president trump will accept that. Remember, there were 1,000 troops in Syria and he called for all of them to be removed. There are troops in the south. Now the president himself said he wants those oil fields in the east guarded in a secure environment. That takes troops. That takes boots on the ground to do that. They're not going to leave those troops in greater danger. They'll want to put the numbers in there they think is best. What about the fight against ISIS? That's what it's about too. Chairman Milley told me that. He said it's all about the fight against ISIS, even guarding the oil fields. They want to keep them away from ISIS. ISIS used the oil revenue to fund their terrorist tactics. Martha Raddatz, great to see you. Martha has a big show this morning. She'll look ahead to the impeachment hearings and she'll cover the latest in the 2020 race and the exclusive interview with general mark Milley. It's all coming up on "This week." Also, stay tuned with ABC news for live coverage of the impeachment hearings. George Stephanopoulos and the entire political team will start our coverage at 10:00 A.M. Eastern on Wednesday.
This transcript has been automatically generated and may not be 100% accurate.