Harry Truman actually said...
Now, Therefore, I, Harry S. Truman, President of the United States of America and Commander in Chief of the Army and Navy, do hereby proclaim that, as a perpetual symbol of our patriotism, the flag of the United States shall hereafter be displayed at Fort McHenry National Monument and Historic Shrine at all times during the day and night, except when the weather is inclement.
07/01/1948