C-SPAN conducted a survey of 91 presidential historians to determine the ranking of the nation's 44 chief executives.  It's the third such survey conducted by the public affairs network, the previous two being taken in 2000 and 2009. The top three presidents have been unchanged over that time: Lincoln, Washington, and Franklin Roosevelt.  Included in the survey for the first time was President Barack Obama. Historians ranked him 12th best. Yahoo News: The poll ranks each US president on various issues, including "crisis leadership", "moral authority", "international relations" and "pursuing equal justice for all". Obama scored particularly high on the "equal justice" scale, coming in third behind only Abraham Lincoln (1861-1865) and Lyndon Johnson (1963-1969). But Obama ranked fifth from the bottom on "relations with Congress", and got a middling 24th best score on "international...(Read Full Post)