I think a key part of this question, is would San Bernardino have happened, or 9/11, if we hadn't meddled in the region? Does Al Quaeda or ISIS even exist if the US had been isolationist and let Afghanistan go to rot? It's easy to look now and say, my god, how can we just let these guys do these horrible things? We can't let them get away with it!
But an absolutist attitude leads to endless war. What if we returned the POWs captured and held in Afghanistan, withdrew our forces, and declared our neutrality and stopped flying missions, applying diplomatic pressure, and supplying any of the combatants in the area?
I'm obviously not sure what the result would be from the "screw you guys, I'm going home" doctrine, but I know it could save us billions of dollars - some of which could be redirected to domestic law enforcement to guard against attacks on our actual soil. It would also make it a lot harder to recruit fighters, without having the pictures of dead kids from a drone strike.
As for the supply of petroleum, oil prices could rise and then we get more jobs in domestic production - as well as a viability incentive to migrate away from the petroleum economy into other energy sources.