The original, 7th-century schism between Sunnis and Shiites isn’t the sole factor in contemporary Islamic violence; but it remains a surprisingly important one.
Read more on American Interest: http://www.the-american-interest.com/berger/2014/06/25/are-people-killing-each-other-today-over-an-election-dispute-in-arabia-more-than-a-thousand-years-ago/