(Hint: the clip was animated in 1939–note the 48 stars in the flag.)
In 1954 the political wingnut combination of the privileged white Daughters of the American Revolution, the Catholic storm troopers fraternal service organization Knights of Columbus, and closet Jehovah’s Witness President Dwight D. Eisenhower pushed Congress to violate the separation of church and state by inserting “under God” into the Pledge.
Fun fact: the original salute to the flag was not placing the right hand over the heart. It was the Bellamy Salute:

