This was my favorite moment of the event, from Kerry:
It's one thing to be certain, but you can be certain and be wrong.
It's another to be certain and be right, or to be certain and be moving in the right direction, or be certain about a principle and then learn new facts and take those new facts and put them to use in order to change and get your policy right.
What I worry about with the president is that he's not acknowledging what's on the ground, he's not acknowledging the realities of North Korea, he's not acknowledging the truth of the science of stem-cell research or of global warming and other issues.
And certainty sometimes can get you in trouble.