If campaigns are a mix of art and science, the decision on when to back a minister who makes a verbal miscue and when to run is all art. There are no firm rules here. This is where gut instinct triumphs over cold calculation. In what he thought was a private moment, Gerry Ritz indulged in some black humour. Who hasn’t? But what we do as private citizens is held to one standard. What ministers do as public servants, even in private moments, is held to another, tougher standard.