Shia and Sunni backstabbing the Muslim world.religion makes sense in international politics. . Only regional balance of power between states can explain contradictions such as: Iran siding with the US against the Taliban; Israel helping Iran (via US) in its war against Iraq whilst fighting their Hezbollah in Lebanon; Israel bombing only Hezbollah or SAA targets in Syria (no attacks on rebels or sunni islamist groups), Baathist Syria and KSA fighting alongside US forces against Baathist Saddam; KSA pressing the US to attack Iran; Gulf states allowing US bases on their soil; Turkey allowing Iraqi Kurdish into Syria to fight ISIS; Iran-backed Hezbollah fighting against Syria-backed Amal in 1988. It's a long list. Balance of power requires states to ignore cultural and ideological differences (or affinities). The fact that there's no pan-islamic unity is due to the fact that states (mainly KSA and Iran but not only) in the region are only interested in their survival and projection of power, and see each other as mutual, fatal threats.
Who killed Iranian nuclear scientist?