Lyndon Johnson actually said...
I also designate the period beginning September 17 and ending September 23, 1966, as Constitution Week; and I urge the people of the United States to observe that week with appropriate ceremonies and activities in their schools and churches and in other suitable places to the end that our citizens may have a better understanding of the Constitution and of the rights and responsibilities of United States Citizenship.
Context
Proclamation 3731—Citizenship Day and Constitution Week, 1966
06/15/1966