The truth is found in books, in school where you obviously have not spent much time, not in movies. Don't believe everything you hear, but what you learn in school.
John Lennon was the President* in the 20th Century (not political); Abraham Lincoln was the US President in the 19th Century.
*President means Lennon was the chief or leader of the defunct The Beatles.
The movie DEPARTED tells misleading phrase for these 2 persons, politically and musically.
From Edgardo Valentino D. Olaes