Another plausible candidate is Nelson Mandela. His tenure as president of South Africa overlapped with Bill Clinton’s presidency, so Democrats never faced a direct comparison between Mandela and a Republican president. But even if you go back to 1990, when Mandela was touring the United States just after his release from prison, his favorable rating in this country was only 58 percent, according to a Boston Globe survey. It was probably about the same among Democrats, since, according to the Globe’s published data, Mandela’s favorable rating was 50 percent among Republicans and 65 percent among independents. But in the same poll, President George H.W. Bush’s approval rating was 78 percent. So mathematically, it’s almost impossible that more Democrats expressed a favorable opinion of Mandela than of Bush.