The High Court’s landmark decision in the NZYQ migration case was a reminder, should one be needed, that the court is the ultimate arbiter of government power.

In the same week that Stephen Gageler was sworn in as chief justice last November, the court overturned a 20-year precedent on immigration detention. More than 150 detainees had to be released, there was a run of bad headlines for the government and the two ministers responsible for dealing with the aftermath were moved in July’s cabinet reshuffle.