Richard Nixon actually said...
Now, Therefore, I, Richard M. Nixon, President of the United States of America, in honor and tribute to the memory of this great and good man, and as an expression of public sorrow, do hereby direct that the flag of the United States be displayed at half-staff at the White House and on all buildings, grounds, and Naval vessels of the United States for a period of thirty days from the day of death.
Context
Proclamation 3907—Announcing the Death of Dwight David Eisenhower
03/27/1969