Luxon survives. But why do National and Labour both struggle with effective leadership?

Phil Walter/Getty Images Christopher Luxon has survived a confidence vote in caucus – his second within five months – and remains prime minister. In a very brief statement this afternoon, he said the National Party caucus is united and he has its full support – despite earlier having spoken on social media about the distraction of “division and disunity”. The party was now “going back to work and moving on,” he said. The entire drama was ignited by reports of dissatisfied National MPs leaking…