Christopher Luxon has promised to hold a referendum on MMP if elected. (Image: NZME)There may be worse ways to project stability than floating a referendum on the electoral system three months before voters hold a referendum on you, potentially without having informed your caucus, but I am finding it difficult to think of them.This must surely be doubly true when the prime minister has just come off a week of self-inflicted turbulence: a tough-love act with businesses at the exact moment business is finding things increasingly tough; a weak defence of citizenship coupled with late outrage at racism; an ad-hoc ruling out of the...