OK, now they've got your attention. In electing Zack Polanski, a media-friendly former actor with an eye-catching vision for a mass movement of eco-populism, the Greens have taken a step into the unknown. And the first task for Polanski is to bring the party with him. Green leadership contests are generally quite polite. This time it has been different, in part due to the personalities but mainly because of the very different visions on offer.