---
title: "National Security Act of 1947 — Definition & Meaning"
description: "The National Security Act of 1947 reorganized U.S. military and intelligence, creating the NSC and CIA, crucial for modern national security."
url: "https://modeldiplomat.com/learn/glossary/national-security-act-of-1947"
---

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Model Diplomat Research Team · Last reviewed June 22, 2026

TL;DR

- The National Security Act of 1947 is the U.
- S.
- Which institutions did the National Security Act of 1947 create?
- What did the 1949 amendments change?
- What predecessor organization did the CIA replace?

[Civil Service & Diplomatic Exams](https://modeldiplomat.com/learn/civil-services/glossary)Updated June 22, 2026

The National Security Act of 1947 is the U.S. statute that reorganized the military and intelligence establishment, creating the NSC, CIA, and a unified national military structure.

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In 1947 President Harry Truman signed the National Security Act, which dissolved the OSS legacy into a new CIA and established the National Security Council that would later approve NSC 68 in 1950.

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