Former Dutch Prime Minister Mark Rutte takes over as NATO boss on Tuesday, charged with holding the Western military alliance together with the war in Ukraine at a critical moment and a pivotal U.S. presidential election approaching.

At a ceremony at NATO headquarters in Brussels, Rutte will take over as secretary-general from Jens Stoltenberg of Norway, who has overseen the organization during a turbulent decade marked above all by Russia's 2022 invasion of Ukraine.

NATO officials and diplomats expect Rutte to maintain Stoltenberg's priorities at the 32-member alliance — rallying support for Ukraine, pushing NATO countries to spend more on defense and keeping the U.S. engaged in European security.