Claim: William R. Tolbert Jr. served as President of Liberia from 1971 until 1980.
Evidence: William Richard Tolbert Jr. -LRB- May 13 , 1913 -- April 12 , 1980 -RRB- was the 20th President of Liberia from 1971 until 1980 , when he was killed in a coup d'état led by Samuel Doe.