"Why are you the one brother still in Wichita?" Mason asked.
"Because my father said, 'Either come back to run the company or I'm gonna sell it,'" said Charles. "And none of the others wanted to come back."
"But that's not the whole reason," Liz continued. "He could have moved many times. [He] could have moved Koch Industries anywhere in the world you wanted to. But this is a great place for raising children and running a business with values."
It was while he and Liz were building their house here in 1973 that Koch confronted his first major crisis as CEO: the Arab oil embargo. "I thought we might go broke, bankrupt" he said.
The scariest time, said Koch, was when there was a takeover attempt -- "by stockholders, or some of my family -- that was pretty scary -- and all the lawsuits that followed it. That was pretty depressing."
In the early 1980s the Koch family broke into open civil war, when Bill and Fred Jr. challenged their brothers for control of Koch Industries. The battle would drag on for nearly two decades.
- Blood and oil ("60 Minutes," 11/27/00)
- Report: Koch Brothers Made Sales to Iran (CBS Moneywatch, 10/03/11)
And while Charles and David prevailed, Charles says the settlement prevents him from talking about it.
To spread his free-market philosophies, in the '70s Koch co-founded the libertarian think tank, the Cato Institute, to advocate for a radically smaller government with reduced regulation and no subsidies.
But during the administration of President George W. Bush the Kochs decided to get more active.
"He's a fine person," said Koch. "I'm sure he meant well. Then he grew government more than just about any president before him, and he got us into counter-productive wars. So that's when I decided we needed to get into politics."
The Koch Brothers have helped fund a complex network of political action committees and advocacy groups, many of them tax exempt, so donors don't have to be disclosed. The network, which now rivals the Republican National Committee in its financial clout, will spend $300 million in this next election year.
Mason asked, "Do you think it's good for the political system that so much what's called 'dark money' is flowing into the process now?"
"First of all, what I give isn't dark," said Koch. "What I give politically, that's all reported. It's either to PACs or to candidates. And what I give to my foundations is all public information. But a lot of our donors don't want to take the kind of abuse that I do. They don't want these attacks. They don't want the death threats. So they aren't going to participate if they have to have their names associated with it."
"But do you think it's healthy for the system that so much money is coming out of a relatively small group of people?"
"Listen, if I didn't think it was healthy or fair, I wouldn't do it. Because what we're after, is to fight against special interests."
"Some people would look at you and say you're a special interest."
"Yeah, but my interest is, just as it's been in business, is what will help people improve their lives, and to get rid of these special interests. That's the whole thing that drives me."
"There are people out there who think what you're trying to do is essentially buy power."
"But what I want is a system where there isn't as much centralized power, where it's dispersed to the people. And everything I advocate points in that direction."
Koch-backed groups were among the early donors to the Tea Party movement.
"What do you think of the Tea Party?" Mason asked.