Assad has been doing the most killing of ISIS.
Assad is only fighting ISIS in the Damascus suburbs, with limited action.
The Russians, Iranians, and Syrians are fighting the rebels.
In Syria, only the west is attacking ISIS.
Assad has lost the country, it will be partitioned. Aliwites will run the west and Sunni will run the east, the Kurds will fight it out with Turkey. Assuming Iran agrees. Hezbollah will attempt to take the Golan, aided by Iran. Israel has been assassinating Hez leaders and Iranian Generals in Golan for 3 years.
Our country is best benefited by not entering Iraq or Syria (and Lebanon) with boots on the ground. Let them fight it out. It will bleed the Russians and Iranians and the Saudis as well.
Look for fireworks on the Persian Gulf before the end of summer.