(10-7-15) Putin has begun airstrikes against ISIL (ISIS) forces in Syria for two reasons: 1/ To shore up his popularity at home by showing that Russia is still a player and 2/ Putin had a vested financial interest in keeping the Assad Regime in power because itís a regime in which he has a huge degree of control over since Syria still owes Russia $8 billion, which Russia at some point would like to collect.
This is a debt that the Federal Republic of Russia had inherited from the former Soviet Union. Unlike most of the Western powers which wrote off the debt, Russia never writes off debt because they know they can use it as a political tool.
Also Assad knows that heís safe in Putinís hands because if he is overthrown, thereís only one place he can go and thatís to Russia.
Thatís the only place heís got to go to avoid war crimes trials is someplace that will take him in and thatís Russia.
Iran fits into the picture because they are a Shia-dominated government while the ISIL (ISIS) movement is something Iran can not control as they would be able to like Hamas for instance.