I retired sort of willy-nilly and only after I started writing the column did I suddenly discover there were all these things out there that I hadn't learned about. And so my mission became to try to educate future retirees about what they were going to face and what they needed to know.

I'm the only president that's ever visited Africa south of the Sahara Desert. I went to two (African) countries while I was president, and I didn't know the potential of that continent, nor the challenges that faced those people. Now I do. To a much greater extent I didn't understand the [widespread] problems in our own country, from a personal point of view. I was dealing with billions of dollars that would be allocated for education or health or welfare or housing, or whatever. But I didn't know from a personal point of view the people that actually were in need or that were the recipients of those quite often inadequate and ill-designed programs.

Kopp ’89 Discusses Education Reform, Looking Beyond the Classroom | Princeton Alumni Weekly

Now, it's been very hard for me to accept that. I never - I felt like - I always felt like I could blow it and nothing would never happen until this happened. So now, it's - no matter how hard I practice, it just seem like I can't do the plays I did.

I was fortunate even from that point of view because I got a very good research collaboration agreement with Upjohn, the American Upjohn company. So that could help me to go on with my research.