Zimbabwe’s High Court on Saturday forced the country’s chief justice to retire, ruling that an extension of his term by the president is illegal.

The ruling is a major setback for President Emmerson Mnangagwa, whose party in May pushed through constitutional amendments that critics said concentrated power in the hands of the president.

Amid a furor, Mnangagwa used his new powers to extend Chief Justice Luke Malaba’s tenure by 5 years on May 11, three days before the justice’s scheduled retirement. Judges in Zimbabwe retire at 70, but the recent constitutional amendment gives the president the power to extend the terms of Supreme Court and Constitutional Court judges by 5 years.

The Young Lawyers Association of Zimbabwe and others sued, arguing that the constitution also stated that Malaba and all current Supreme Court and Constitutional Court judges cannot benefit from the amendment. Only judges appointed after the amendment can.

A panel of three High Court judges on Saturday agreed and said Malaba had “ceased being a judge and chief justice.”

Malaba, viewed by critics as Mnangagwa’s ally, was head of the Constitutional Court when it ruled that a 2018 presidential election in which the opposition narrowly lost was valid. Critics viewed the term extension as a tactic aimed at ensuring that Malaba stayed in the judiciary’s top office ahead of Zimbabwe’s next presidential and parliamentary elections, which are scheduled for 2023.