The following is a script from "Senator Tom Coburn" which aired on Dec. 21, 2014. Lesley Stahl is the correspondent. Ira Rosen and Habiba Nosheen, producers.
Tom Coburn, the conservative Republican senator from Oklahoma, announced earlier this year that he has prostate cancer and will be ending his term two years early.
This is an interesting man. He's an obstetrician who has delivered over 4,000 babies. Called the "Godfather of the Tea Party," he has been a powerful and effective force against government spending. He opposes gay marriage, he's against abortion rights and says global warming doesn't exist. And yet, he became one of Barack Obama's closest friends in Congress. It may be Washington's most unlikely friendship, but it is a lesson that political opposites can work together in highly partisan and dysfunctional times.
In this, Coburn's farewell interview before leaving the Senate at the end of the month, he says some things you may never have heard a conservative Republican say about this president of the United States.
Tom Coburn: My relationship with Barack Obama isn't based on my political philosophy or his.
Lesley Stahl: What's it based on?
Tom Coburn: It's based on the fact that I think he's a genuinely very smart, nice guy. I just love him as a man. I think he's a neat man. You don't have to be the same to be friends. Matter of fact, the interesting friendships are the ones that are divergent.
That Tom Coburn is close to Barack Obama is seen as a betrayal by many of his fellow Republicans, but he doesn't care.
Tom Coburn: I'm proud of our country that we elected Barack Obama. I mean, it says something about us nationally. You know, it's kind of like crowning your checker when you get to the end of your checker board. Here's another thing that says America's special: Barack Obama, president of the United States.
"My relationship with Barack Obama isn't based on my political philosophy or his."
The friendship began in 2005 as freshmen senators, Coburn the conservative obstetrician from Muskogee, Oklahoma, and Obama the liberal state senator from Chicago. They often teamed up to pass important pieces of legislation.
[Tom Coburn: It's my pleasure to introduce to you a good friend of mine, since we went through orientation together, Senator Barack Obama.
Barack Obama: Thank you, Tom.]
Last year, TIME magazine named Coburn one of the 100 most influential people in the world, and it was President Obama who wrote the tribute...and this year, after learning that Coburn has cancer, the president spoke about him at a Prayer Breakfast.
[Barack Obama: A great friend of mine who I came into the Senate with, Sen. Tom Coburn. Tom is going through some tough times right now. But I love him dearly even though we're from different parties.]
Lesley Stahl: It's interesting that you're friends with the president because--I guess people think he doesn't have any friends in the Senate.
Tom Coburn: The president hasn't done a great job of reaching out. It's not his personality style. I mean, you know, he's not well-suited to be a back slapper, sit down and let me tell you this dirty story before we get down to business. I mean, he's not one of those kinds of guys. He's a serious guy.
And so is Coburn. He's also a maverick who is always making someone angry.
Tom Coburn: Am I frustrating the senator from New Mexico? You bet!
He has called his colleagues cowards, called Majority Leader Harry Reid "a complete a-hole," for which he would later apologize, and says anybody off the street could do a better job than the senators there now.
Tom Coburn: I see 'em make decisions every day that benefit their career, rather than the country. And that's what's so sickening about Washington. To me, it's about our future. It's not about the politicians. And we've switched things around where now it's about the politicians and not the future of the country.
It seems the public agrees with him: one poll showed that Americans have a higher opinion of witches, the IRS and hemorrhoids than Congress.
"I see 'em make decisions every day that benefit their career, rather than the country. And that's what's so sickening about Washington..."
Lesley Stahl: Congress's approval rating in the last poll I saw, seven percent.
Tom Coburn: Who are the seven percent of the people who actually think we do a great job?
Lesley Stahl: You have said, "Let's get rid of them all and start all over again."
Tom Coburn: If ya wanted to fix things, that's what I would do.
Lesley Stahl: Get rid of everybody?
Tom Coburn: I mean, if I was king tomorrow, that's what I'd do.
And if he were king he would take a meat ax to the federal budget. He has made cutting out fat in government programs his Holy Grail.
[Tom Coburn on Senate floor: Actually I'lI think I'll just tear it up. It's time we stop borrowing money against the future of our kids.]
His power comes not from creating legislation, but from killing it with procedural roadblocks that have gummed up the works.
Stephen Spaulding: I think he is the number one champions of gridlock in the U.S. Senate.
Stephen Spaulding, who focuses on the Senate for the political watchdog organization, Common Cause, says senators often have to go to Coburn to get their bills released and that has given him significant power.
Stephen Spaulding: He has found every loophole in the Senate rulebook that he can to grind things to an absolute halt.
Lesley Stahl: He says he does it so the government won't grow out of control?
Stephen Spaulding: There's a question there as to whether he has been substituting his judgment for that of the Senate, and I think that's what has led to absolute political paralysis in Washington.
What Coburn does is put a "hold" on the legislation -- as he did this week on a Veteran Suicide Prevention Bill -- and a hold stops a bill in its tracks and paralyzes the Senate. That's how he got his nickname Dr. No.
Lesley Stahl: How many holds have you put on?
Tom Coburn: Thousands.
Lesley Stahl: Thousands? Let me ask you about some of the holds that we've come up with. Extending unemployment insurance.
Tom Coburn: Uh-uh.
Lesley Stahl: Veterans' benefits. You even held up a bill called "The Paralysis Bill" to help people in wheelchairs.
Lesley Stahl: Thirteen veterans' groups attacked you when you wouldn't agree on the veterans' benefits.
Tom Coburn: Yeah.
Lesley Stahl: You're the reason the place has shutdown!
Tom Coburn: No it isn't.
Lesley Stahl: Well, all these holds, you're one of the reasons.
Tom Coburn: The holds...there's no debate on those anyhow. Nobody ever knows about 'em.
Lesley Stahl: Well, they would pass if you didn't put the holds on them.
Tom Coburn: That's right. And you'd grow the government and our problems would be worse, not better.
The thing is -- Coburn is proud of his contrariness and his refusal to "go along." He got his values growing up in Muskogee, Oklahoma - where he says he had a happy childhood. It's a church-going, Middle America kind of town where he was taught to be independent and not waste money. He still lives there on a 40-acre farm.
[Tom Coburn: I got three stalls out there for horses and it got a big hay loft in it.]
He and his wife Carolyn, a former Miss Oklahoma, raised their three daughters here, one is a nationally known opera singer.
Carolyn Coburn: We've known each other since the first grade.
Carolyn Coburn: Third grade I was on his list of girlfriends.
Lesley Stahl: How many did he have?
Carolyn Coburn: Three! I was the last.
Tom Coburn: She's telling the story.
Carolyn Coburn: I remember the list. Dun, Sara, Ditten.
The biggest influence on Tom Coburn's life was his father. After graduating college, he went to work for his dad in the family optical business.
Lesley Stahl: So you told me in Washington that your father was an alcoholic.
Tom Coburn: Uh-huh. (affirm)
Lesley Stahl: Now that can't be easy when you say that you had a happy childhood.
Tom Coburn: Well, it doesn't take away from the great things that my dad did.
Lesley Stahl: Did it change you... Did it... Is it kind of a key to you?
Tom Coburn: (pause) Mmmm...I don't know
Lesley Stahl: But why is it welling up like this?
Tom Coburn: (long pause) I think clinically if I were to analyze it, probably didn't do good grieving.
Carolyn Coburn: We could spend about a week grieving over all the things we've missed grieving over. That'll be a fun week. (chuckle)
At the age of 31, Coburn left his father's business and went to medical school. After practicing as an obstetrician for 11 years --
Carolyn Coburn: One day he came home and said, "I'm gonna run for Congress." I said, "Congress of what?" (chuckle) I mean, I'm-- like, "what is he talking about?"
Lesley Stahl: Do you know anything about politics at this point in your life?
Tom Coburn: No.
At their favorite BBQ restaurant in town, he told us being a doctor didn't hurt in his first campaign in 1994 for the House of Representatives.
Tom Coburn: You deliver 2,000 babies or better-- 3,000 by that time. And that's, you know, at minimum, three people each. And then if you take grandparents or grandparents of siblings and aunts and uncles, you know, you get-- a 100,000 votes outta that (laughs).
After three terms in the House, he returned to Muskogee and continued to deliver babies until 2004 when he won a Senate seat. One of the first things he did - true to form -- was pick a fight - with the late Republican Senator Ted Stevens who had been the chairman of the Appropriations Committee. Stevens wanted to build a bridge project in his home state of Alaska.
Tom Coburn: We're gonna put $456 million to go to an island of 50 people? You know, I ask--
Lesley Stahl: The bridge to nowhere, right.
Tom Coburn: The bridge to nowhere. And-- and this is right after Katrina happened. And so I offer an amendment to take that money from Alaska and repair the stuff in Louisiana.
[Ted Stevens from floor debate: So I have been asked several times today will I agree to this version or that version of senator from Oklahoma's amendment? No.]
Tom Coburn: I lost that. But I won that. I absolutely won that because the American people saw that and they said, "Wow."
Lesley Stahl: But what happened to you? They really came after you over that. You were still practicing medicine.
Tom Coburn: Yeah, they-- they--
Lesley Stahl: You were still delivering babies.
Tom Coburn: They took that away.
Lesley Stahl: They took that away.
The Senate ruled that it was a conflict of interest to be a senator and practice medicine on weekends and made him stop.
Tom Coburn: There were several people that I really irritated with this bridge to nowhere. And they happen to sit on the Ethics Committee, you know.
Lesley Stahl: They shut you down?
Tom Coburn: They whacked me pretty good.
He says he was persona non grata with his Republican colleagues. But he did have his alliance with the senator from Illinois.
[Obama in press conference: I've had the pleasure of working with Sen. Coburn on a range of issues, but I can't think of one that's more important and more timely.]
Tom Coburn: The one thing we did is we got our staffs together and said, "We wanna do some things together, find the areas you think that we can work-- together. And let's do 'em." And so we did.
Lesley Stahl: You wrote bills together?
Tom Coburn: Uh-huh (affirm). And got 'em passed.
Lesley Stahl: You got 'em passed?
Tom Coburn: And got-- and got 'em signed. We did a lot of stuff on lowering the rates on student loans and re-calculating all that to save a lot of people a lot of money in the future going forward.
They did that and more together, despite their many philosophical differences - on global warming and all the social issues. But none of that has disrupted their friendship.
Tom Coburn: I've told him, "Don't let the S.O.B's get you down," when he's been getting-- he-- I'll call him up and say, "Hey, I'm pulling for ya," you know.
What's funny is that he himself has been one of the S.O.B's, railing at the president when he disagrees, say on health care or immigration.
[Obama at prayer breakfast: I keep praying that God will show him the light and he will vote with me once in a while. (laughter) It's going to happen, Tom.]
But now Tom is retiring. As he moves on to a new battle - with an advanced case of prostate cancer.
Lesley Stahl: Now, did you have to take chemo and radiation and all--
Tom Coburn: Yeah, I'm in the midst of that right now.
Lesley Stahl: Look at you. You're totally energetic. It's not sapping you of--
Tom Coburn: Well, it will eventually, you know. Yeah.
Lesley Stahl: Will you lose your hair?
Tom Coburn: Maybe.
Carolyn Coburn: Oh. Oh. (chuckle)
Tom Coburn: I got Bill Clinton hair, don't I?
Lesley Stahl: I know.
Tom Coburn: Everybody is gonna die from something. And so the deal is how to use each day to move things forward for both you and the people you love and the country you love.
Earlier this month, Coburn delivered an emotional farewell speech to his Senate colleagues whom he has served with - and occasionally blasted over the last 10 years.
Tom Coburn: And a thank you to each of you for the privilege of having been able to work for a better country for us all. I yield the floor. Yield the floor.