GWEN IFILL: Now one of the nation's most famous veterans takes a look at American heroes from each of the nation's conflicts, most largely unknown, in a new book, "Thirteen Soldiers: A Personal History of Americans at War." The authors are Sen. John McCain and his longtime collaborator Mark Salter.

I sat down today with the Arizona Republican to talk about the book and also about what to expect from the new Republican Senate majority.

Sen. McCain, thank you for joining us.

In your latest book, you decided to write about 13 soldiers, not yourself, and from the Revolutionary War to our latest enterprises in Afghanistan and Iraq. Is there a through-line of similarity between all of those?

SEN. JOHN MCCAIN, (R) Arizona: I think there is a similarity, in that, no matter where they came from or what their gender or race was, that they were dedicated to serving the country, sometimes with honor and integrity, and sometimes maybe not so much, but they — courage.

They served with courage, and I think they epitomized many aspects of that particular conflict. In other words, our first guy, Joseph Plumb Martin, who was in the Revolutionary War at 15, almost starved to death, literally almost starved to death.

GWEN IFILL: And died in poverty.

SEN. JOHN MCCAIN: Yes, and died in poverty without a pension. Well, actually, it took them 30 years before a pension.

But compare that with Mike Monsoor, who was a man who sacrificed his life for the lives of others. It wasn't a question or food. It wasn't a question of equipment. It was a dramatic change, but each of them served and sacrificed, and ordinary people who did extraordinary things.

GWEN IFILL: And Michael Monsoor, of course, threw himself on a grenade and got the Medal of Honor.

But you remember a time, as a Vietnam veteran, when veterans weren't treated with that kind of respect. Have you seen that evolve over time, or are we still, as Americans, basically stuck in a position where we say, thank you for your service, but don't know what else to do with that?

SEN. JOHN MCCAIN: I think we have come a long way from Joseph Martin, when they literally were discharged and given pieces of paper that they could convert into money or services, to today, where we do a great deal.

But I think there's been ups and downs, Gwen. After the Vietnam War, unfortunately, as you know, many people blamed the veteran and the young 18-, 19-year-old draftee. I think it's really a shameful chapter.

But I also think we're trying to make up for that, and I think we are making up for it. I see companies and corporations stepping up. I'm proud of my home city of Phoenix, Arizona, where there are no homeless veterans. They have provided lodging for every homeless veteran in our city.

GWEN IFILL: But there's patriotism. There's practicality. There's certainly practicality in hiring veterans. And then there's the politics of this whole thing.

Do they contradict one another often when it comes to veterans?

SEN. JOHN MCCAIN: Oh, I think sometimes it's used for political gain.

But I am happy that we have had now in this last election some veterans, including Joni Ernst, Dan Sullivan, and Tom Cotton, that have served recent conflicts. You don't have to be a veteran to be a great senator and a great leader on military affairs, but it does help to have some veterans present, so that they can give us the perspective that only those with that kind of experience can provide.

GWEN IFILL: Well, so then tell me, if you had to recommend one of these stories in this book, which one would you recommend?

SEN. JOHN MCCAIN: I think I might recommend Oliver Wendell Holmes Jr.

He came from the Boston Brahmin family. He joined the Harvard Regiment, which was a mixture of Harvard and Ivy League, Harvard graduates and German-speaking Americans. He learned the lessons of war. He was changed by the war, but yet he went on to serve as a justice of the United States Supreme Court.

One little anecdote. Every day at work, he had a tin ammunition box that he would bring his lunch to work with, because always reminding him of the conflict. And, of course, it was the bloodiest, most fratricidal conflict by far we have ever been through, and it defined America.

GWEN IFILL: When Congress returns in January, you are going to be chairman of the Armed Services Committee. And you will have a different kind of platform. We see playing out even today the U.S. strategy on ISIS, another beheading of an American aid worker.

What, as the chairman of the committee and with this new platform, would you do that would be different than what's being done right now?

SEN. JOHN MCCAIN: We are facing challenges unprecedented in my lifetime. We need to have hearings to start with from some of the wisest people in America.

I want to get Henry Kissinger and Zbig Brzezinski and George Shultz and Jim Baker and people — and I also want to get some proven military leaders, like General Petraeus and many others, to come down and talk directly to the members of our committee in Congress so they can tell us what our challenges are.

GWEN IFILL: What is the value in bringing people from past administrations to advise this administration? Because you don't trust this administration?

SEN. JOHN MCCAIN: I think they have learned the lessons.

They have lived it from that side of the river and they know what their challenges are, but also they have a great grasp of the overall situation in the world. Many of these new members, particularly, have never been involved with the big-picture issues.

GWEN IFILL: I guess what I'm curious about, the pushback that the White House offers is, the Republicans are critical, but they don't have their own solution.

SEN. JOHN MCCAIN: You know, that's interesting to hear, because everything that Lindsey Graham and I and Joe Lieberman said would happen would happen, we said long ago, we are going to need a lot more boots on the ground. Guess what? The president, just 1,500 more.

And I guarantee they will need more and they will need to arm the Free Syrian Army and they will have to ignore the boundaries between the two countries. What we're seeing is a gradual escalation, which then the escalation loses much of its impact.

I mean, when we decided we were going to bomb ISIS, we gave them a week's warning. I mean, it's crazy. But everything that we have prescribed that needed to be done, if it had been done, we wouldn't be where we are today.

GWEN IFILL: Has the well truly been poisoned with the White House at this stage for the final two years of this presidency because of executive action or threats of executive action?

SEN. JOHN MCCAIN: I think it's hurt the environment and I think it should be challenged in court, because the president for months said that he didn't have that kind of authority.

And now he is exercising the kind of authority that he said he didn't have. And I think it's clearly unconstitutional. But, frankly, shutting down the government is not the answer.

GWEN IFILL: But you are going to have to fight that government shutdown fight again, aren't you?

SEN. JOHN MCCAIN: Oh, I hope we will prevent it from happening. Both Sen. McConnell and Speaker Boehner have said that that is not the solution, so I hope we can prevail.

GWEN IFILL: Sen. McCain, thank you very much.

SEN. JOHN MCCAIN: Thank you, Gwen.

GWEN IFILL: My conversation with Sen. McCain continues online, where we discuss the value of military, as well as civilian public service.