Harry Truman actually said...
Now, Therefore, I, Harry S. Truman,President of the United States of America, on the occasion of the sesquicentennial of President Washington's Farewell Address, do hereby call upon the officials of the Government to display the flag of the United States on all Government buildings on September 19, 1946
Context
Proclamation 2701—One Hundred and Fiftieth Anniversary of Washington's Farewell Address
09/05/1946