In an interview with "CBS Evening News" anchor Norah O'Donnell, Senator Bernie Sanders talked about the cost of his health care plan, his relationship with former rival Hillary Clinton and the impact of the impeachment trial of President Donald Trump. Sanders told O'Donnell it's "disappointing" to not be meeting with voters in Iowa, but acknowledged the importance of attending the trial in Washington, D.C.

Read O'Donnell's interview with Sanders below.

Is the impeachment trial putting Sanders at a "disadvantage?"

Norah O'Donnell: So impeachment's now gonna keep you here in Washington for about 10 days and not in Iowa. Does that place you at a distinct disadvantage?



Senator Bernie Sanders: Well, let me be frank. I mean, obviously, when we had planned out our schedule, trust me, we were not planning to be in Washington this week. We had set up a number of town meetings all over the state. We usually bring out good crowds. So it is disappointing to me not to be in Iowa, talking to the people there.



O'Donnell: Don't you think it's important business?



Sanders: Here? Well, of course, it is. And I am accepting my constitutional responsibility. But what I'm saying, obviously, it's at a disadvantage.



O'Donnell: Do you think it places Biden at an advantage over you?



Sanders: Politically in the last week or so of the campaign, yeah, I think it does. I mean, he and others, not just Biden, are able to go out, talk to people. That's really important.

On his role in the impeachment trial



O'Donnell: On Saturday, the president's legal team will make their presentation. Is there anything they could say that would change your mind?



Senator Bernie Sanders: Look, I am functioning as a jurist. I want to hear all sides. But I will tell you right now what has upset me the most and upset the American people is: How do you have a fair trial when you don't have witnesses when you can't get documents? What is the President, what are the Republicans hiding?

"It's unusual" for a senator to be seated for "nine hours"

O'Donnell: We don't get to see your colleagues during the trial. The cameras are not pointed at the senators. Take us inside. I mean, what is everybody doing?



Sanders: I think it's unusual for a senator, especially somebody who's running for president (I think we have four or five of those on the floor right now) to be seated for nine hours. It's just not the way the Senate usually works. So I think what people are trying to do is to listen as intently as they can.



O'Donnell: Are the senators staying awake?



Sanders: In most cases.

How much will health care cost?

O'Donnell: I want to talk about your agenda. You want the government to pay for everyone's health care.



Sanders: I want the United States to do what every other major country on Earth does: guarantee health care to all people as a human right.



O'Donnell: But you've been confronted by voters on the campaign trail and acknowledge that there will be job losses as a result of such a plan. Is that a hard sell, that your plan?



Sanders: Yeah, it would.



O'Donnell: Is gonna cost?



Sanders: Sure, it might be a hard sell. The American people want a health care system that works for them, not for huge profits for the drug companies who are ripping us off every day and the insurance companies. At the end of the day, we will create more jobs. Will there be some job loss? Yes, there will. We're gonna create more jobs. We need more doctors. We need more nurses. We need more psychologists and psychiatrists to help us deal with the opioid epidemic. There'll be a net plus of jobs.



O'Donnell: You're a self-proclaimed socialist.



Sanders: "Democratic," put in there, please.



O'Donnell: Thank you. Your agenda has promised free health care for everybody, free college tuition, and to pay off people's college loans. The price tag for that is estimated to be $60 trillion over ten years, correct?



Sanders: Well, look. We have political opponents.



O'Donnell: You don't know… You don't know how much your plan costs?



Sanders: You don't know. Nobody knows. This is impossible to predict.



O'Donnell: You're gonna propose a plan to the American people, and you're not gonna tell 'em how much it costs?



Sanders: Course I will. Do you know exactly what health care costs will be, one minute, in the next 10 years if we do nothing? It will be a lot more expensive than a Medicare-for-all single-payer system.

His reaction to Hillary Clinton saying "nobody likes him"

O'Donnell: It was also mentioned by Senator Hillary Clinton, who said that while you two were campaigning against each other that you also said that she was unqualified to be president. She said that you foster a toxic culture in your campaign where your prominent supporters, Bernie bros, attack women. And will you denounce those attacks?



Sanders: I have, of course. I am sorry for what Secretary Clinton had to say. I know she said that nobody likes me, right? I mean, this is not the kind of rhetoric that we need right now when we are trying to bring the Democratic Party together to defeat the most dangerous president in American history.



O'Donnell: When's the last time you spoke with Senator Clinton?



Sanders: It's been quite a while.



O'Donnell: Do you think it's important to have her supporters if you were the nominee?



Sanders: Well, right now my job is to win in Iowa. It's to win in New Hampshire, do everything we can. But what Secretary Clinton did indicate, I was glad to hear this, is that she would support the Democratic nominee. And if that's me, I look forward to her support.





His feud with Warren

O'Donnell: I want to turn to your feud with Senator Warren. Did you and Senator Warren ever discuss her allegation that you said a woman couldn't win the presidency?



Sanders: I'm sorry. I really-- I know the media likes that issue, but I'm not gonna get into that issue. We had it out. Senator Warren is somebody I've known for 25 years, have a lot of respect for. We're gonna go forward together. And I have the feeling we'll be working together.

Can Sanders defeat Trump?

O'Donnell: President Obama's former campaign manager, Jim Messina, said-- this about you in a matchup with President Trump, "I'm a business guy, the economy's good, and this guy's a socialist," that that's what Trump would say about you. Do you acknowledge it would be an uphill battle against President Trump?



Sanders: You've obviously seen the latest polls, right?



O'Donnell: Uh-huh.

Sanders: How am I doin'? I think the last CNN poll had me seven points ahead of Trump. I think we are the strongest-- campaign to defeat Trump, and I will tell you why. To defeat Donald Trump, you're gonna need an incredibly large voter turnout. I think our campaign is the campaign of energy, of excitement that can reach out to young people, reach out to working-class people who today are sick and tired of a government and an economy that works for the people on top and ignores them.

Uniting the Democratic Party

O'Donnell: Can you unite the Democratic Party? We've just talked about criticism from Senator Warren, criticism from Senator Clinton, criticism from the Obama camp.



Sanders: You know, Norah, as you well know, when there are camp-go back to 2008 and look at Obama and Clinton. You think there was criticism between the two? There was bitterness between the two.



O'Donnell: I know. The primary stretched through the summer.

Sanders: That's right.



O'Donnell: Beginning of the summer.

Sanders: That's right. I mean, that's what politics is about. You know, unfortunately, that's the way it is. But I have no doubt that if I become the nominee, we're gonna be able to unite the party because, number one, every Democrat and a majority of independents know how dangerous Donald Trump is. How he's trying to undermine democracy. How he's running a corrupt administration. How he is a racist and a sexist, and so forth. We're gonna unite the Democratic Party. And the issues that we are talking about, raising the minimum wage to a living wage, health care for all, dealing with the global crisis of climate change, that is an agenda that will bring the American people together to defeat Trump.

His battle with Joe Biden on Social Security

O'Donnell: Let me ask you about Vice President Joe Biden. He is looking for an apology for a video circulated by your campaign that he says takes his position on Social Security out of context. Will you apologize?



Sanders: No, of course, I won't. Not on that one, I won't. For many, many years as a United States senator, Joe Biden has been on the floor and elsewhere, talking about the need to freeze or cut Social Security benefits. He voted for the Balanced Budget amendment.



O'Donnell: So you believe it is wrong that Vice President Biden supported a freeze of cost-of-living adjustments in Social Security?



Sanders: Absolutely. Bad vote. I voted against it. There are ways to raise money in order to protect the working families of this country. Cutting Social Security ain't one of 'em.



O'Donnell: All right. Senator Bernie Sanders, thank you for being here.



Sanders: Thank you.