President Barack Obama drew the diplomatic line somewhere at the first ever U.S-Africa summit at the White House this week by not inviting Zimbabwe’s brutal dictator Robert Mugabe. But the guest list still included several other African leaders with only slightly better human rights records. The White House promoted the summit as the largest-ever gathering of African leaders in the United States, with more than 50 countries represented. The red carpet was rolled out for Equatorial Guinea's Teodoro Obiang Nguema Mbasogo, who shot or jailed virtually all his political opponents, Gambia’s Yahya Jammeh, who threatened to ‘cut off the head’...