This has been an extremely disquieting day, for several reasons. First and foremost, the US Ambassador to Libya was murdered in cold blood last night, along with three other diplomats -- and horrifying images of the carnage are being beamed around the world. A few basic facts via Reuters:  The U.S. ambassador to Libya and three embassy staff were killed in an attack on the Benghazi consulate and a safe house refuge, stormed by Islamist gunmen blaming America for a film they said insulted the Prophet Mohammad. Gunmen had attacked and set fire to the U.S. consulate in the...