Josh Marshall is no right winger, but he too seems to think it is time to end ISIS. A couple of excerpts:
I don't know what the precise best policies here are. But I do have a clear idea of several of the building blocks. The first recalls something I said a few weeks ago, which is that it is folly to be actively engaged against both sides in a civil war, which is effectively what we are now doing. Such a policy may have a cynical logic when you have two hostile entities which you want to see wear each other down and pulverize each other - much as we did during the Iran-Iraq War in 1980s. That is not the current situation. The Assad regime, while bloody, does not in any way pose an immediate threat to the United States. We need to redefine our Syria policy around the goal of the physical elimination of ISIS as a territorial entity and the physical elimination of its top leaders. If that means accepting the continuance of Assad family rule in at least rump Syria than we need to accept that - even though he's backed by regional adversaries Russia and Iran. Again, how serious are we about eliminating ISIS? I'd say not very serious if we're still hung up on Assad.
What I do know is this. ISIS is a genuine threat to us and our allies. In recent weeks, they've killed more than a hundred people in Paris, downed a Russian jetliner and appear to have carried out major attacks in Beirut and Ankara. They are a real and present threat. Assad is not a clear or present threat to us. Our policy is a contradiction and a losing one. We can deal with Assad later. In Washington circles it's become a conceit. Our policy in Syria should be to destroy ISIS. Everything else can come after that.
I would add that if we destroy ISIS in convincing enough fashion, some of the other players might be at least a little intimidated.