After the Second World War ended in 1945, much of the world lay in ruins. After enduring a war that spanned nearly the entire globe, the loss of roughly 75 million people, and that cost trillions of dollars in damage, world leaders formed a system of international organizations and agreements to foster cooperation in the post-war world – the liberal international order. The liberal world order, which has governed much of international relations for more than 70 years, works to propagate democracy, market economies, the rule of law, and human rights.

As part of the liberal world order, the United States built a system of alliances in Europe and Asia, which have formed “the backbone of the liberal international order for more than 70 years.” The primary purpose of the alliance system was to maintain the balance of power on those continents against the United States’ Cold War rival, the Soviet Union. These efforts resulted in a series of formal treaty alliances based on collective defense.

U.S. Alliances in Europe

The European continent was nearly devastated after the Second World War. The United States, realizing that communism could potentially spill over into Europe, was instrumental in helping its Western European allies rebuild, particularly through the implementation of the Marshall Plan and the establishment of the Truman Doctrine. In this vein, in 1949, the United States, along with ten Western European countries and Canada, founded the North Atlantic Treaty Organization, or NATO. This multilateral alliance was created to counter and combat the Soviet Union’s desire to spread communism throughout Europe and, to this day, serves as the center of European security.

The NATO alliance has endured quite a bit in its existence. NATO experienced “the transformation of the European security system from East-West confrontation to a Western-centric post-Cold War, during which NATO conducted its first shooting war in the Balkans [in the 1990s].” After that, NATO participated in the wars in Afghanistan and Libya, a conflict in Somalia, among other involvements, and increased its membership total nearly two-fold.

While several countries joined NATO between the early 1950s and late 1990s, much of NATO’s expansion took place in 1999 and 2004, when ten former Soviet satellite states joined the alliance. Since the revolutions of 1989 and the dissolution of the Soviet Union in 1991, the desire of Central and Eastern European countries to join NATO increased dramatically.

While there were and remain some divisions between the NATO member states on expanding membership to these countries, NATO continued to expand. The idea behind this expansion was that membership would promote peace and stability in Europe, particularly among those in Central and Eastern Europe. Today, there are 30 NATO members states. Future expansion is constantly debated within the alliance and is the primary cause of tensions between the alliance and Russia. NATO recently announced that the alliance will be shifting its focus to the rise of China as well.

U.S. Alliances in Asia

Much like Europe, Asia was also ravaged by the Second World War. As a result, the United States established alliances with key partners in the region. In what is referred to as the hub-and-spokes system, the United States, through its bilateral alliances in Asia, had the same goal of countering the Soviet Union and its desire to spread communism.

For one, in 1952, the United States, New Zealand, and Australia signed a mutual defense treaty. Interestingly, New Zealand is no longer included in the formal treaty due to U.S. concerns over its nuclear policies in the 1980s. However, the United States and New Zealand remain close friends, just not formal allies. Australia is often referred to as one of the United States’ closest allies in Asia.

Moreover, the United States and Japan evolved from mortal enemies in the Second World War to close allies through the signing of the Treaty of Japan in 1951. Japan remains the United States’ closest ally in Asia. The United States also signed a mutual defense treaty with South Korea after the end of the Korean War in 1953, with a pledge that both sides would defend one another in the event of an attack.

The United States also has defense treaties with the Philippines and Thailand. The Philippines, formerly a U.S. territory after the United States defeated Spain in the Spanish American War in 1898, signed a treaty in 1951. The United States and Thailand were both signatories of the 1954 Manila Pact of the former Southeast Asia Treaty Organization (SEATO). Though the group disbanded in 1977, the Manila Pact outlines the U.S. security commitments to Thailand.

The United States and Taiwan were also formal allies when the U.S. signed a defense treaty with the Republic of China. This changed, however, when the United States officially recognized the People’s Republic of China as the sole government in 1979. Consequently, there are no security guarantees. Yet, the United States sells arms to Taiwan, much to China’s consternation. While the United States no longer has formal alliances with Taiwan and New Zealand, it still maintains alliances with Australia, Japan, South Korea, the Philippines, and Thailand with a renewed focus on the rise of China.

Conclusion

After the Second World War, with much of the world in ruins, world leaders established the liberal world order. A major part of this order was the United States’ alliance system, designed to maintain the balance of power in Europe and Asia and counter the Soviet Union, its primary adversary. Over the past seven decades, these alliances have formed the backbone of the liberal world order and stand strong today.