From Washington's tangled perspective, tolerating the existence of ISIS, and containing its territorial footprint to designated areas in Iraq and Syria, is preferable to upsetting strategic allies Turkey and Israel who depend on ISIS to fight their decades-long battles with Hezbollah and the PKK.
Since the militaristic leaderships of Turkey and Israel don't want to reach a peace deal with the PKK and Hezbollah then why not go to war with them with their professional armies? We always hear how the Israeli army is the best in the region, and that the Turkish army is a disciplined juggernaut. Okay, very well. Then why rely on a bunch of barbaric Jihadis to fight your enemies and carry out your political goals? Why use ISIS as a proxy army?
The answer is that neither the Israeli army nor the Turkish army are powerful enough to subdue what are basically people movements. The PKK and Hezbollah have grassroots support who can't be defeated militarily. They have to be engaged politically. They arose in reaction to injustices and insults, and will only disarm if the states of Turkey and Israel change their behaviour.
The militaristic leaderships of Turkey and Israel have tried for decades to eliminate these two groups with state force but have failed miserably. The Israeli army lost in 2006 when it invaded Lebanon. And the Turkish army has not been able to defeat a gureilla group in its own backyard, which counts as a loss.
So these two losing states figured that the tool of terrorism in the form of ISIS might work better at subduing their stateless and politically popular enemies than their traditional armies. And, tactically speaking, they're not wrong. ISIS has the effect of driving populations out of their homes by terrorizing and brutalizing entire towns. This is a barbaric practice the Turkish and Israeli armies would not be able to get away with politically in the international media. So ISIS really has been a godsend for the leaders of Turkey and Israel.
Now, what is Washington supposed to do in this crazy situation? It will upset Turkey and Israel if it chooses to destroy ISIS, which it is fully capable of doing.
Russia does not have such complicated ties to either Turkey or Israel, plus it is genuinely threatened by the spread of radical Islam on its borders, which is why it has acted so energetically in Syria.
Who knows, maybe the Obama administration is secretly happy that Putin decided to take action in Syria. Numerous reports have been published over the years that say President Obama is not on the best of terms with either Erdogan or Netanyahu. Could Putin be doing him a personal favour by hitting ISIS so hard? Again, who knows. Anything is possible.
People assume that President Obama is protecting ISIS with his soft-touch policies in Syria, but in reality he's protecting Turkey and Israel. They would be the biggest losers if ISIS comes under Uncle Sam's full wrath. The terrorists in ISIS should thank their lucky stars that Washington is on the side of Turkey and Israel in their respective fights.