I agree that it's better to be discover the truth than continue down a path of ignorance. But being "proven wrong" is not so nice a position to be in, especially if one is a politician. Far better: to realize that "mistakes were made" or "the situation on the ground has changed" or some such, than be proven wrong. It's just not rhetorically very effective to be proven wrong.

Also interesting are the reasonable skeptics versus the dogmatists.

The courtroom of public opinion isn't interested in guesses, cautious estimates, the need for more data and so forth. Look at climate change. The proponents of one theory are certain the world will end if we don't change. Everyone else is a skeptic, which means they don't know, or are unsure, which means they don't know. More and more the voice of certainty overrides the voice of cautious reason.

Oh and Peter please don't feel obligated to respond to everything I say. I'm just voicing some long held opinions and hoping to help you generate some conversation and interest. Also feel free to email me privately any time.
-dave