Mandela was one of the few people one can say was truly great; a paragon of strength, dignity, forgiveness and wisdom, he endured terrible adversity for his cause, and when he won, he eschewed vengeance and led his country into a (relatively) peaceful new era. And here is the Onion's take.
At some point today, the world's political leaders will pay tributes to Mandela. When David Cameron, the UK's Prime Minister says his words (as he must, regardless of whether it'd be the decent thing to do), let it not be forgotten that the Federation of Conservative Students of which he was a senior member at the time called for Mandela to be executed as a terrorist.