He's worried that our staggering debt, if un-checked, could signal the beginning of America's decline.
"There is a long, clear history of nations rising to greatness and leadership, and then falling. And interestingly, I quote an historian who says, 'It always starts with the money.' You know, first they spend themselves into a corner, borrow themselves into a corner. And the rest of the fall, including military defeat sometimes, flows from that."
Daniels says we urgently need to balance our nation's books - as he did in Indiana, by taking big government OUT of the equation and letting free enterprise take over.
"The heart of American society is the private sector," he said. "Government should be there not to dominate it, to dictate to it, make all the decisions, but to do those things we have to do together to make private life flourish."
Sit in on a few meetings with him, and his focus on the bottom-line is hard to miss, whether he's tackling an environmental project, welfare reform, or child protection.
For now, he'll continue working on Indiana's problems. And as for what the future may hold? While he won't be our next president, who knows what the next phone call may bring?
"I always say that one day the phone rings, and something interesting that seems useful is on the other end," he said.
"To be Vice President?" asked O'Donnell.
"That wasn't the call I was hoping for!" he laughed.
"But you wouldn't rule that out?"
"Oh, I don't ... you don't rule anything out, I suppose," Daniels said.
For more info: