Until we tap into our own natural resources, that funding will not and can not be cut off. We rely too heavily on that oil, and that cutting would likely hurt us worse than ISIS. Not in the short run probably, but definitely in the long run. Of course, the best case scenario is to tap into our own resources so that we are no longer dependent on imports.
The waiting to stop ISIS is a double edged sword, IMO. The longer we go without doing anything, the more people will realize the justification of our last incursion into Iraq. Of course, some will tout that we were the cause of this current problem, in which case they'd be partially right. But if we hadn't stepped in, instead of ISIS, it would (and was) Saddam doing the same thing.
As I said before, historically, there will always be war in the Middle East. I think our best bet would be to implement a policy of conditional non-intervention. As in we do not intervene until something causes us to have to, such as a possible threat to America, or humanitarian aid on a large scale such as the current thousands trapped on the mountain.
As America, we seem to have a self imposed responsibility to save the world. While I am all for that if we can, we can't. We can't afford it. We have to take care of ourselves first, so that we can actually help out if needed. We need to be more introspective and fix ourselves, then we can focus on the world. It's similar to the mote/beam analogy of the Bible, only applied to ethics and economy.
We know there will always be war there. The only way to assure there won't be would be a totalitarian take over and implementation of a satellite state. This goes against what we collectively stand for in America, as well as what I personally believe. We'd basically be substituting ISIS with a totalitarian dictatorship made up of Americans.
It's a sticky situation no matter which way you lean. IMO, as I said, our best strategy would be to let them hash it out themselves unless and until it becomes a situation that we can no longer remain outside of.