Lyndon Johnson actually said...
In commemoration of the anniversary of this battle and the men who lost their lives in the struggle for control of the Nation's Capital, I request appropriate officials of the Government to display the flag of the United States on all Government buildings in the District of Columbia on that day at half staff until noon and at full staff after noon.
Context
Proclamation 3598—Monocacy Battle Centennial
07/06/1964