“Four times in New Zealand history, there’s been quite significant turning points,” says David Seymour. He takes a miniature chocolate bar from the bowl in front of him and twirls it on the table, listing them off: the Treaty of Waitangi, marking the beginning of the nation. New Zealand granting universal suffrage, the first country in the world to do so. The creation of the current, party-based political system. And the free-market reforms brought in by the Labour government in the 1980s. “I just make the point that … in my view, there’s never been reform from the right.” Seymour,...