The curse of modern politics is an epidemic of good intentions and bad outcomes. Policy after policy is chosen and voted on according to whether it means well, not whether it works. And the most frustrated politicians are those who keep trying to sell policies based on their efficacy, rather than their motives. It used to be possible to approach politics as a conversation between adults, and argue for unfashionable but effective medicine. In the 140-character world this is tricky (I speak from experience).

The fact that it was Milton Friedman who said “one of the great mistakes is to judge policies and programmes by their intentions rather than their results” rather proves the point. He was one of the most successful of all economists