Congressional testimony this week showed the appalling lengths to which the Obama administration went to cover-up its mishandling of last fall’s terrorist attack at the U.S. mission in Benghazi, Libya, but President Obama’s precise role in the cynical operation remains hidden.Americans still don’t know what President Obama knew and when he knew it. We don’t know what exactly he did when he learned on Sept. 11, 2012 that U.S. officials in Benghazi were under attack. Obama may have gone to bed while the attack was in progress, leaving others in the administration to develop a politically expedient cover story calculated...