Naoero is set to formally withdraw from the Rome Statute, the treaty behind the International Criminal Court. President David Adeang announced the decision at the UN General Assembly this month, citing the court’s “increasing irrelevance,” according to Reuters.

The United States congratulated Naoero after Assistant Secretary of State Michael DeSombre met the country’s deputy foreign minister. DeSombre said Naoero joins “a growing number of nations standing up for their sovereignty against the ICC’s illegitimate overreach.”

At the General Assembly, President Donald Trump had urged all ICC member states to resign “from this rogue institution, immediately.” Naoero, a Pacific island nation formerly known as Nauru, was the only country to follow his lead, Reuters reported.

The European Union rallied behind the court. EU foreign policy chief Kaja Kallas said the bloc has tools to defend the ICC against potential US sanctions.

Why it matters: Naoero’s exit is the first concrete result of Washington’s pressure campaign against the court, and a test of whether others follow.