We've described the Syrian civil war as a war between the Sunni majority rebels and the Assad government to some degree representing everyone else - Alawites, Shias, Christians, Druze, etc.
The government is backed by Shia Iran and Hezbollah (of Lebanon), as well as Russia, for its own reasons. The rebels are backed by the Sunni Arab nations with oil wealth. In other words, it is a battle between Shia and Sunni nations, fought by proxy forces.
The Sunni-Shia conflict is also underway in Iraq as this Reuters article for Yahoo News indicates. It is rare when several days go by without a suicide bombing in Iraq aimed at gatherings of one group or the other, this particular bombing aimed at Sunnis. Sectarian conflict is also prevalent in Pakistan.
The New York Times weighs in with an article saying Syria is splitting into three zones: Sunni jihadi, Shia Government, and Kurd. That works.
Kurds are tired of Arabs of either sect. They are trying to create Kurdistan, cobbled together out of northeastern Syria, northern Iraq, and maybe more if they can pry it loose from Turkey.
