I think it's obvious they believe, we'll eventually switch to helping them by fighting against Assad and his Russian backers. We didn't even hit ISIL first, but rather another group of former AQ members called the Khorasan Group that were planning imminent attacks against the US and Western interests.
When you have such a mess of different interests and adversaries all mixed up, they can easily turn. All it would take is for Syrian troops to miscalculate, like they did with a fighter getting shot down over the Golan Heights.
Einstein, "science without religion is lame, religion without science is blind."
Instead of letting the Afghani go back to tribal rule with each tribe ruling their own little corner of Afghanistan along with the shifting alliances, we alienated over half the tribes of the Northern Alliance. All 14 tribes were once our allies, now half of them would like nothing better than to kill us. Mainly because we forced our brand of government on them instead of letting them choose their own. I do not think I have to say a thing about Iraq.
Early voting in Georgia. On the 20th of October this old Goldwater conservative voted against both Donald Trump and Hillary Clinton by casting my vote for Gary Johnson. Neither Trump or Clinton belong within a million miles of the Oval Office.