YOUR GOVERNMENT has been asked frequently in recent months why a Ground Observer Corps of civilian volunteers is needed to help defend our country. After a thorough evaluation of our Air Defense System 1 issued a statement, on July 12, 1952, endorsing the necessity that this Corps operate 24 hours a day.1 The foremost reasonwhy "Operation Skywatch" is carried on day and night is to have in being an organization capable of detecting low-flying aircraft that have avoided detection by our radar warning system and thus to prevent a surprise attack upon our country.
1 See Item 202.
On this December 7, 1952, the 11th anniversary of the surprise attack on Pearl Harbor, I wish to call to your attention the fact that an attack of this nature can happen again. Because of the immense destructive power of the atomic bomb we must maintain vigilance so that our cities and our industries will be less vulnerable to devastating attack.
I therefore call upon all citizens who reside in communities which have been designated as possible enemy air approach areas to volunteer their services for this vital task.
Note: On December 2, 1952, the White House announced the development of another defense plan, to be placed in operation within 3 months, which would also minimize the effectiveness of an air attack on the country. The plan, called CONELRAD (Control of Electromagnetic Radiation), was developed on the basis of Executive Order 10312 whereby the President authorized the Federal Communications Commission either to silence radio stations or to control their operations so that electromagnetic radiations might not aid the navigation of hostile aircraft, guided missiles, and other devices of similar purpose.
The release stated that more than 1,000 privately-owned standard broadcast stations had already volunteered to participate in the CONELRAD system, which provided, in case of an air raid alert, that they switch to one of two predesignated controlled frequencies (640 kc or 1240 kc) in order to broadcast to the public a continuous flow of accurate, official information, news, and civil defense instructions.
Harry S Truman, Statement by the President on the Need for "Operation Skywatch." Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/231204