U.S. Intelligence

The United States built its modern intelligence apparatus almost entirely in the twentieth century, and mostly in response to war. What began with wartime codebreakers and a handful of agents grew, after 1945, into a sprawling secret establishment — the CIA, the FBI's domestic security arm, the NSA's global eavesdropping, and more than a dozen other agencies.

The Cold War was the great engine of its growth. Locked in a shadow struggle with the Soviet Union, the United States poured resources into spying, codebreaking, covert action, and counterintelligence. Intelligence agencies overthrew foreign governments, ran spy networks, and raced to penetrate one another's secrets.

That secrecy bred abuses. Domestic surveillance of citizens, illegal break-ins, assassination plots, and programs like the FBI's COINTELPRO came to light in the 1970s, prompting the Church Committee investigations and new limits on what the agencies could do. The tension between secrecy and accountability has defined American intelligence ever since.

The September 11 attacks and the digital age reopened those debates, expanding surveillance powers and mass data collection — and exposing them again through leaks. American intelligence remains one of the most powerful and least visible parts of the government, perpetually balanced between protecting the nation and threatening its liberties.