04/29/1964
https://www.presidency.ucsb.edu...
"Now, Therefore, I, Lyndon B. Johnson, President of the United States of America, do hereby authorize and direct the Secretary of State to invite, on my behalf, such foreign countries as he may conside..."
"Let us make ourselves worthy of that generosity by pledging to Him our everlasting devotion."
"For all the blessings that have been bestowed upon our nation during the past 12 months, it is a small thing to give thanks to Almighty God."
"I urge that these observances specially emphasize the need for immediate private and public participation."