NATO: The World’s Largest Alliance
Trace NATO’s history and learn how the organization’s mission has evolved over seventy years.
As World War II ended and the relationship between the Soviet Union and other Allied powers deteriorated, the United States, Canada, and a group of ten European countries organized themselves for a new geopolitical reality. In 1949, they created the North Atlantic Treaty Organization (NATO), an alliance with the aim of preserving a free, integrated, and democratic Europe, particularly against the Soviet Union.
In international relations, an alliance is a group of countries that come together to promote their common security interests. In many cases, alliances promise military support if one member is threatened, a formal commitment known as mutual security. The core of NATO’s strength comes from Article 5 of its founding treaty—a commitment that an attack on one member country will be considered an attack on the entire alliance.
All kinds of countries benefit from alliances. For smaller, weaker countries that lack resources to mount a proper defense, joining an alliance can be the only realistic path to maintaining security and deterring potential foes. Larger or stronger countries use alliances to increase their military might and, sometimes, their influence over smaller countries, while also discouraging nuclear proliferation among smaller countries.
For over seven decades, NATO has endured, even as the common foe that it was organized against—the Soviet Union—disappeared. It successfully protected its members against Soviet aggression; no NATO member was ever attacked by the Soviet Union. Today, the alliance consists of thirty member countries and is an essential reason that Europe has remained mostly conflict-free since the end of World War II. But it has also recently taken on faraway missions in places like the Middle East to prevent humanitarian suffering, with mixed results, and come under increased scrutiny due to many of its European members not spending enough on their defense. These challenges come as many NATO countries consider Russia a renewed threat to Europe’s security.
This timeline explores NATO’s history—from its origins as a bulwark against the Soviet Union to its present-day operations far from Europe’s shores—and examines the effects of its expanding membership, evolving mission, and recent funding concerns, all of which point toward an uncertain future.