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National Security

Last Updated: 2006

The notion of national security has taken on different meanings throughout the course of U.S. history. Simply put, national security can be defined as the acts taken by a state to insure the sovereignty and integrity of its territory and also maintain the safety of its citizens and national interests. The threats posed to the United States have varied and required a myriad of responses to guarantee national security.

In early American history, the country wanted to secure its right to trade and to fulfill Manifest Destiny by extending the national border from the Atlantic to the Pacific. To protect trade, the United States invaded British Canada in 1812 to have a bargaining chip when treaties between France and Great Britain greatly restricted international commerce. This caused tension that led to the War of 1812 and a military stalemate between the United States and Great Britain. In order to annex the territories of California and New Mexico, President James K. Polk provoked a war with Mexico in 1846. In both instances, the United States was able to protect or annex its territory and secure its rights to trade.

The United States began to look outward at the end of the nineteenth century. Trade and business interests were established abroad. Alfred Thayer Mahan and Theodore Roosevelt succeeded in augmenting the Navy in order to both protect trade and secure the borders from outside insurgencies. When Cuban revolutionaries slashed and burned sugar fields, many of which belonged to American companies, and the Spanish were suspected of blowing up the U.S.S. Maine, the U.S. government found its best interests were to wage a war with Spain. The war was quick and relatively bloodless, and was a success in protecting American interests.

Protecting American interests resulted in the country’s involvement in the first major conflict of the twentieth century. America was brought into World War I when Germany used its U-boats to sink merchant and passenger ships. American products were destroyed and American lives were lost, thus leading President Woodrow Wilson to call for war. Entry into World War II came when the Japanese empire attacked the U.S. naval installment at Pearl Harbor in Hawaii in December 1941. It was only after the success of the Allied forces against Germany and Japan in 1945 that the modern-day notion of national security emerged.

The post–World War II years saw the need to completely restructure the defense and intelligence apparatuses. The National Security Act of 1947 produced the National Security Council, headed by a national security advisor who would be a direct advisor to the president and the Central Intelligence Agency (CIA) to coordinate intelligence, and created a secretary of defense to replace the secretary of war. American policy makers believed these adaptations were necessary to properly protect interests at home and to be able to contain Communist threats abroad. To further insure that the Soviet threat was contained, in 1947 the Truman Doctrine allocated $400 million to help Turkey and Greece, and the Marshall Plan gave billions in loans to European countries rebuilding after World War II, both in an attempt to contain communism. Soon after, in 1950, National Security Council Paper 68 (NSC-68) stated that the Soviet threat must be contained through an active and militaristic American policy. The Soviet Union was the threat to American interests that had to be checked in order to provide adequate national security.

The interest of national security throughout the Cold War years was centered on the containment of communism. In recent years, national security has taken a dramatic turn. Since September 11, 2001, the prevalent threat to the United States and its wellbeing was that of terrorism. That fateful day saw a terrorist group, not a nation-state, use airplanes to attack the World Trade Center Towers in New York and the Pentagon in Washington, D.C. Policy makers quickly fashioned a new Department of Homeland Security and a new system of alerting the public of shifting terrorist threat levels. While acts of terror have attacked American interests in the last twenty years and resulted in a rapid response, the horrors of September 11, 2001, shaped the need for an almost complete overhaul of national security aims, the likes of which had not been seen since the National Security Act of 1947. Modern times see the threat of terrorism as the greatest danger to our national security, and it will no doubt guide foreign and domestic policy initiatives for years to come.



John Lewis Gaddis, Surprise, Security, and the American Experience (Cambridge, MA: Harvard University Press, 2004); Charles Gleek, Michael Grillo, and Robert P. Watson, eds., Presidential Doctrines: National Security from Woodrow Wilson to George W. Bush (New York: Nova Science Publishers, 2003); Michael J. Hogan, A Cross of Iron: Harry S. Truman and the Origins of the National Security State, 1945–1954 (Cambridge: Cambridge University Press, 1998); Peter J. Katzenstein, The Culture of National Security: Norms and Identity in World Politics (New York: Columbia University Press, 1996); and Michael Mandelbaum, The Fate of Nations: The Search for National Security in the Nineteenth and Twentieth Centuries (Cambridge: Cambridge University Press, 1988).