Why did the United States create the Central Intelligence Agency after World War II?

The United States created the Central Intelligence Agency (CIA) in 1947 primarily to address systemic failures in its intelligence apparatus that had become apparent during World War II.12

Prior to the agency's formation, U.S. intelligence gathering was fragmented among the Federal Bureau of Investigation, the military, and the Office of Strategic Services (OSS). This decentralized system suffered from intense inter-agency rivalries, duplication of effort, and a lack of coordination, which often prevented critical information from reaching senior policy makers. For example, these communication gaps contributed to the government's failure to anticipate the attack on Pearl Harbor.13

Following the war, the National Security Act was signed into law to reorganize the nation's security structure. The CIA was established to serve as a central organization responsible for correlating, evaluating, and disseminating foreign intelligence to ensure a more unified and efficient approach to national security.432