Russia's missile defense was turned off PERIOD even before the strike ..why? because if even one error occurred by the Russian system (Russia makes junk and they know it) shooting down one U.S jet ...Russia would have huge problems of which is fighting a REAL SUPER POWER 1000 times bigger than it.  The Russian ships doing the "missile shield" (turned off) was only to scare Obama.(it worked)...now the ships are STUCK as  political  showmanship...and Assad just found out his buddy Putin...isn't defending him..and Russia may actually bail on him. Why?..because the Russian economy is broken and needs other friends.