I just stumbled upon Arthur C. Clarke's First Law of Prediction
. While he is a scifi writer (2001: A Space Odyssey
), with all the caveats that that may entail, I like the cut of his jib:
When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
Perhaps replace "scientist" with "politician" and it might be worthwhile advice for our statesmen. Optimism, forward thinking, positive progress, and upward movement are probably a better fit for us, as a species, then negative and reactionary behaviour.