South Australian Premier Jay Weatherill is a relatively rare breed -- a calm and optimistic politician -- but he is realistic enough to go into the new year knowing his government is in peril.

The government's performance this week, in the wake of royal commission powers being given to an inquiry into an alleged cover-up of s-xual abuse at an Adelaide school, has been unconvincing at a time when it needs to be clear and assured. It enters the final cycle of this term with the emotive issue of protecting children hanging over its head.