The multilateralism that we practice at North Atlantic Treaty Organization (NATO) derives from the North Atlantic Treaty, also known as the Washington Treaty in honor of this city, where it was signed on April 4, 1949. Next year we will be celebrating seventy years of this remarkable document, which provides the legal foundation for NATO's continued adaptation to the changing transatlantic security environment. One recent example of this adaptation came last year when Montenegro joined the Alliance. Montenegro's accession received almost unanimous advice and consent in the Senate. That is an important sign of the continuing vitality of interest in multilateralism here in Washington.