Why Would the Saudis Deliberately Crash the Oil Markets?

Simple: to undermine Tehran.

http://foreignpolicy.com/2014/12/18/why-would-the-saudis-crash-oil-markets-iran/?utm_source=Sailthru&utm_medium=email&utm_term=Flashpoints&utm_campaign=2014_FlashPoints%20[Manual]RS18%2F12