Notwithstanding any possible constitutional provisions that these surveillance activities may violate, the NSA is legally permitted to conduct intelligence-gathering activities on U.S. soil and on U.S. citizens. Another major federal intelligence agency – the Central Intelligence Agency (CIA) – is statutorily prohibited from gathering intelligence on U.S. soil.

This limitation was implemented by the same legislative act that created the CIA itself – the National Security Act of 1947, signed into law 66 years ago today.

The Act was created in the aftermath of World War II and in anticipation of the emerging Cold War.

During World War II, inadequacies in civil‐military policy coordination became painfully apparent, as did shortcomings in coordination within the armed services and in intelligence-gathering.

After the war, there were calls to remedy the problem of poor military coordination by merging the U.S. Army (along with its air force division) and U.S. Navy into a single department. Although the Army and its air force were in favor of this action (as was most of Congress), the Navy was opposed.

Recognizing the overwhelming support in favor of unifying the U.S. military, Navy Secretary James Forrestal understood that outright opposition would not stop Congress from acting. Instead, Forrestal sought out his former business colleague Ferdinand Eberstadt to evaluate the situation and propose alternatives tenable for the Navy.

Eberstadt found that military coordination was not the only problem. Rather, he also saw the need for improved civilian‐military coordination and better intelligence operations. Eberstadt submitted a report that identified the serious deficiencies in both intelligence-gathering and -sharing between the military and various civil agencies within the U.S. government.

Largely based on Eberstadt’s recommendations, the National Security Act was signed into law on July 26, 1947 by President Harry Truman.

The Act consolidated the Department of War and the Department of the Navy into the National Military Establishment. It also created the Department of the Air Force from the division that was formerly a part of the U.S. Army.

The National Military Establishment, later renamed the “Department of Defense” in 1949, was headed by the Secretary of Defense. The National Military Establishment began operations on September 18, 1947 – the day after the Senate confirmed James Forrestal as the first Secretary of Defense.

The Act also created the Joint Chiefs of Staff and the National Security Council, both of which are a central part of national security operations today.

Finally, as stated above, the Act created the CIA. The same provision of the Act that created the CIA also specifically stated that the Agency would have “no police, subpoena, or law enforcement powers or internal security functions.”

This limitation is widely understood to limit CIA activities within the U.S. to those that could be justified only to the extent they supported the CIA’s primary foreign intelligence mission.

This restriction arose over concerns among Congress and the American public that the CIA may become a “Gestapo” that spied on and secretly targeted U.S. citizens. Thus, the CIA was completely denied any internal security powers.

Arguably, with the burgeoning Cold War, national security concerns were much greater when the National Security Act was being considered than today. If the implementation of the CIA’s restrictions is of any indication, the size of the threat apparently didn’t outweigh concerns for the protection of civil liberties.

It remains to be seen if Congress acts with the same high regard for the protection of civil liberties in its response, if any, to the NSA domestic surveillance activities of today.

 http://westlawinsider.com/legal-research/today-in-1947-the-national-security-act-is-signed-into-law/