Jens Stoltenberg, one of NATO’s longest-serving leaders, is stepping down from his role as Secretary-General on Tuesday, making way for former Dutch Prime Minister Mark Rutte to take over. Stoltenberg, who has been in office since 2014, guided the alliance through some of its most challenging times, including Russia’s annexation of Crimea and the subsequent military buildup by NATO.
During his nearly decade-long tenure, Stoltenberg oversaw significant changes in NATO, driven by growing security threats from Russia. He is NATO’s 13th secretary-general, with only Dutch diplomat Joseph Luns serving longer.
A ceremony at NATO’s Brussels headquarters will mark the leadership transition. The Secretary-General’s role includes managing the organization’s agenda and acting as the spokesperson for the 32-member alliance. Typically, continuity is emphasized during such transitions.
Rutte’s appointment comes as the alliance faces mounting challenges, especially as Russia’s war in Ukraine approaches its 1,000th day. Political uncertainty within NATO is also high, particularly with the U.S. heading into an election year. As NATO’s most influential member, the U.S. plays a critical role in the alliance’s stability.
On the battlefield, Russian forces are making gains in eastern Ukraine, while Ukraine has managed a small victory in Russia’s Kursk region. Despite this, Ukraine’s army remains outmatched in terms of manpower and resources.
Rutte’s immediate challenge will be maintaining strong support for Ukraine among NATO allies. Since the invasion, Finland and Sweden have joined the alliance, bolstering its ranks.
The upcoming U.S. election could bring further complications. Former President Donald Trump, who is running again, previously criticized NATO allies for not spending enough on defense. His past rhetoric raised concerns about the U.S. commitment to NATO’s security guarantees, a foundational principle of the alliance.
Trump has also been critical of U.S. aid to Ukraine and recently suggested that President Volodymyr Zelenskyy should have made concessions to Russian President Vladimir Putin before the war began in 2022.