Its a tough deal because the world has gotten small enough that you probably can't just leave them alone to their own demise.
With what I know, and I'm sure that isn't much, I would destroy all of their ability to fund war. I really would. When ISIS takes an area, I would destroy the oil facilities and wells in that area. And, I would tell Iran we'll do the same thing there if need be. And then do it if need be. I think that is where I would start.
Well, we would be doing the things that a semi-sane kingdom would attempt to do.
There’s a reason why ISIS hasn’t gotten very far in, say, Saudi Arabia. They’d get mercilessly squashed by the kingdom, which is strong enough to do it thus far, though worried about its longer term prospects.
If we start thinking in terms of kingdoms, I think we would be thinking more realistically. There could be relative peace. The US itself may, after struggle, decide to chuck out its own idea of God permanently. The end times is no excuse not to attempt to wisely do good in the middle times. The end will be marked by a loss of the resources needed to do that, i.e. people who are willing to believe in a God who blesses.