Sweden officially became the 32nd member of the North Atlantic Treaty Organization yesterday after its prime minister, Ulf Kristersson, deposited its document of accession with the US government, the treaty's caretaker. The Nordic country's admission to the mutual defense pact formally ends its over two centuries of military nonalignment.

Sweden adopted a neutral stance to European military affairs after losing significant territory—Finland—to Russia in 1812 during the Napoleonic Wars. This approach—as well as its relatively isolated location in the north—allowed the Scandinavian country of 10 million to avoid involvement in major conflicts. Since it joined the European Union in 1995, the Nordic nation's neutrality has given way to increased military cooperation, and recent years have seen the return of conscription and expanded defense budgets.