The United States government considered Nelson Mandela a terrorist until 2008. Mandela was a designated terrorist 18 years after he was released from prison, 15 years after he won the Nobel peace prize, and 14 years after he was elected president of South Africa.
Let that sink in for a moment.
In 1962, the U.S. government considered Mandela to be "the most dangerous communist" outside of the then Soviet Union. It was subsequently revealed that a CIA agent provided the South African government with the information necessary to apprehend him and land him in prison for 27 years.
The indignity suffered by Mandela during every visit to the United States — as a "terrorist" he had to get special clearance to enter the country — was finally wiped clean by an act of Congress just five years before he died.