A foreign born communist is not worthy of an American half-mast flag. That being said we shouldn’t lower the flag for Mandela either.
Margaret Thatcher did a hell of a lot more for Britain and the United States than Nelson Mandela did for South Africa.
The best that can be said about Mandela is that he mellowed in his older age. So did George Wallace, but the left still can't forgive him for his publicity stunt in front of the school house door.