Former New Zealand prime minister Jacinda Ardern bade farewell to parliament a few weeks ago. Ardern had resigned as PM in January, saying she no longer had ‘enough in the tank’ to lead the country. After half-a-decade in charge, and regularly feted on the world stage, Ardern has all but vanished as a ubiquitous figure of the age; but more striking is the extent to which her political legacy has, too.