The invasion in 2003 was incredibly short-sighted. Whether blinded by hubris, or promises of personal gain, or whatever, the war was incredibly ill-conceived and the occupation was also a disaster. Paul Bremer’s decision to wholly disband the Iraqi Army (as well as basically every other institution of government in the country) was one of the biggest national security blunders of recent memory.
The unraveling currently occurring in Iraq had me thinking a few things today. First, Saddam’s rule shows that an ethnically and religiously fractured (and fictitious) country like Iraq can only be centrally ruled by an agnostic, oppressive dictatorial regime. That the situation on the ground would devolve along sectarian and ethnic lines once the US removed the stabilizing force of the Ba’ath party was both predictable and inevitable. The US handed the country to one sect (Shiites) over the others and then paid off the remaining factions and tribal leaders to gain their support for the new government (the Petraeus anti-insurgency plan, ‘the surge,”). Once we left, Maliki simply un-did all the relationships we created for him among the Sunnis and Kurds and proceeded to banish them from political life (and commit other repressive acts). It’s also worth noting that the presence of a Shiite government in Iraq was a huge boon for the Iranians (and then we turn around and complain of their growing regional influence… haha, classic America).
Second, because we chose to support a sectarian government in Iraq, we now find ourselves woefully entangled on both sides of the widening conflict. Whereas in the past it was America’s modus operandi to support secular dictators (such as Mubarak in Egypt, Saddam in Iraq and even Gaddafi in Libya can be included), effectively elevating US policy above sectarian disputes and insulating it from claims that it supported one or the other side, the US now finds itself supporting Sunni rebels in Syria and the Shiite government in Baghdad; working with the Saudis on Syria and the Iranians on Iraq (and possibly a wider rapprochement). In my opinion, this type of thing represents precisely the type of “entangling alliances” about which Thomas Jefferson spoke when he counseled for a non-interventionist foreign policy in his First Inaugural Presidential Address in 1801.
Third, we lack sufficient national interests in Iraq to justify large-scale military intervention. Oil is definitely not an interest – except insofar as we want to prevent any large shakeups in international markets that could harm the global economy – especially since the USA has just reclaimed the mantle of #1 oil producer in the world, overtaking Saudi Arabia. ISIS doesn’t appear to pose a direct threat to the United States – both in evaluating their stated goals (an Islamic State) and our quite-dominant capabilities for targeted actions. And, even if despite these points ISIS does desire and achieve some limited actions against the West, I don’t agree that "we must fight every terrorist group abroad to prevent them from hitting us at home." I think recent history has shown that the opposite is true; that military engagements in the Middle East and abroad (especially when conducted on the behalf of one internal group over another) breed further resentment and hatred of the United States and help to galvanize the next generation of fighters. Note that most of those calling for increased, direct actions against ISIS in Iraq are discredited neoconservatives (like Bill Kristol, Charles Krauthammer, Dick Cheney, John McCain and Lindsay Graham). There's no reason to think the outcomes of their current prescriptions of military action would be any different than the last time we did what they suggested (which is what we have NOW).
Contrary to the fatalist justification for not intervening that "the sects are involved in a centuries old never-ending conflict," it’s not clear that the ideological and literal warfare between the sects is inevitable. The New York Times had a good piece yesterday pointing out that entrenched interests (read: Saudi + GCC, Iran, etc) have diligently exploited these sectarian rifts for political purposes, inciting civil and sectarian war, but that the sects haven’t actually been at war with (or even hated) each other this whole time. Rather, there are spikes in the sectarian hatred usually caused by something else – power struggles between invested elites. If that’s true, it would bolster the legitimacy of our prior strategy for enforcing the Sykes-Picot borders in the Middle East – supporting non-ideological / secular elites in these countries.
This is one of the true lessons of America's wars in Iraq: that in order to secure one of these fictitious nations populated by competing sectarian groups, only a strong man with sectarian allegiance to none can govern from the center.
I think, absent that, our best option for intervening is to try to cut the head off of ISIS, then push forward with a partitioning of Iraq to create Sunni, Shiite and Kurdish states. However, non-interventionism is also looking like a good option. At this point, we are basically fanning both sides of the dispute, which must end if we’re to resolve the broader Iraq/Syria conflict. Hopefully, the US can achieve a breakthrough with Iran on their nuclear program that will provide the legal and political space for the two countries to make progress on other issues (such as Iraq/Syria). If we can’t install secular dictators to effectively govern the two countries, then maybe reaching agreements with the two main regional powers is our best method for tampering the conflicts. (One last point on this- those opposed to rapprochement with Iran often argue that Saudi Arabia will be furious and will seek out a new benefactor, such as Russia or China, but while either could provide money and weapons, neither is willing or capable of being the security guarantor in the region with naval and air power, so they will continue to rely on the United States for the near to mid-term future).
Iraq and Syria are a complete mess and the US wouldn't be crazy if it decided to do nothing. Maybe if we can get a whole “inclusive regime, new political process, blah blah blah” then we can entertain propping up that government in Baghdad. Removing Maliki should be a first step towards any efforts to support Baghdad against the regions. Absent that, doing nothing, or abandoning hopes for "democracy" and instead supporting strongmen seem to be our only good options.