“I know what this job takes, and I know that I no longer have enough in the tank to do it justice. It is that simple.” And with that, New Zealand Prime Minister Jacinda Ardern had told the world she had burned out. She had left the building. It was the right decision for her personally and it’s certainly up to New Zealanders to decide on their own reaction. She will resign by Feb. 7 so the centre-left Labour party will have to quickly choose a new leader for an October election Ardern might well have lost. But it was...