I think first in terms of Yugoslavia in the 1990s, which also saw the collapse of an untenable-once-placed-under-pressure nation-state, followed by atrocities.
My own pet theory as a very much non-expert who wastes some attention on the news is that Iraq and Syria need to be broken into smaller pieces based on ethnicity: Kurdistan, Sunni-stan, and Shia-stan, and perhaps others. From what I understand Kurdistan is already more or less operating, just without an official declaration of statehood; there still isn’t an Iraqi “state” per se. “Iraqis” don’t really fight for Iraq: they fight for their ethnic groups.
Breaking countries into single-ethnicity pieces may be the major lesson of Yugoslavia and perhaps World War II, which had the unfortunate effect of making many European countries close to monoethnic.
There are problems with this solution in the Middle East (e.g. Turkey and Kurds) but there also seem to be many problems with the status quo, to the extent there is a status quo.
Perhaps the only thing average individuals can do is attempt to use less oil at the margin (shift from a hybrid car to a plug-in hybrid when necessary, from a standard car to a hybrid, and there are others), since oil is indirectly funding so much of the violence. When I read about large-scale, seemingly intractable problems, I often want more writers to ask, “What is an average person supposed to do?” and then attempt to answer the question.
Note, however, that Iraq and Syria also have cousin marriage problems that may destabilize the state and empower smaller groups.
Still, take this analysis skeptically, given my views on Iraq War II when it happened, and given too that foreign policy seems like William Goldman’s description of Hollywood: nobody knows anything. The CIA famously missed the fall of the Soviet Union. Pretty much no one expected World War I. The U.S. thought Vietnam, Afghanistan, and Iraq War II were going to go well. And so on.
The U.S. has been fighting little wars (apart from the obvious big ones) for its entire existence, and while the tools have changed the rhetoric only sometimes has. In addition, overall I see the world as getting better. One account of this can be seen in Steven Pinker’s The Better Angels of Our Nature. Most of Latin America is doing well. Even Africa is doing better than is sometimes assumed. The thing the U.S. and the West in general most have on our side is time and immigration patterns. Pretty much no one is fighting to emigrate from their current country to, say, Russia. Even current scare-story China sees more Chinese leaving than others trying to enter. Most parts of the world that aren’t tremendously fucked up are attempting to emulate the U.S. and Europe in many, though not all, dimensions. The long-term trends are positive for most people in most places even if Syria is a disaster.
To my mind giving everyone their own sandbox is a move in the right direction, despite opposition.