There's a lot of books out there about how you lead change in business, but I've certainly not seen any... on how you do that in public institutions.

I had no difficulty as Secretary of Defense moving from the Bush administration to the Obama administration.

Well, Israel, obviously, thinks of the Iranian nuclear program as an existential threat to Israel.

If possible, to be in a position to announce who is going to step in as the interim immediately. And if possible, to announce who you're going to nominate to replace that person. For that to be somebody of impeccable integrity and reputation disarms a lot of the worst criticism that it's some kind of a power play. It's a professional approach to replacing a senior official, which is always going to get a lot of attention.

I fired a lot of senior people myself and I think the key, when you feel compelled to remove a senior official, is essentially to have all your ducks in a row at the beginning. Have everybody understand what the rationale was.

No policy has proved more successful in making friends for the United States, during the cold war and since, than educating students from abroad at our colleges and universities.

I wish I could set deadlines for the Congress, but that's just not the way the Constitution is written.