OK, since I have no answers about what to do about the situation in Iraq, I am going to once again engage in my usual obfuscating putdown of nearly all commentators who exhibit ignorance about the situation over there. About all I can say is that it looks like maybe the Obama people are not quite as ignorant as the Bush people were, and maybe a bit more cautious.
Anyway, again I have to thank the intrepid Juan Cole for producing a map from the early 1100s that shows a configuration of states that somewhat resembles what exists now on the ground de facto in the area of Syria and Iraq. There was no unified Iranian state, but much of what is now eastern Turkey was ruled already by the Seljuq Turks (western part by the Byzantines), Syria minus its northern part was ruled by the Atabeg dynasty; approximately what is now Israel was the Crusader Kingdom of Jerusalem; southern Iraq plus Kuwait and some more was the Abbasid Caliphate, and the area approximating what is now controlled by DAEESH (or ISIS or ISIL, if you prefer, a bit more on that in a minute) was a non-very-long-lasting state ruled by Imad al-din Zengi, hence the name "neo-Zengist," including what is now northern Syria and most of what is now northwestern Iraq. The only thing that would come of out of this state of any importance was Saladdin, who retook Jerusalem from the Crusaders, and the province in modern Iraq now ruled by DAEESH, Salahuddin, was named for him using his Arabic name (he was actually Kurdish).
So, more obscuranta. DAEESH is the most widely used transliteration of the Arabic name for the group, usually called either ISIS or ISIL. The latter is really silly, as the "L" stands for "Levant," a completely anachronistic and Orientalist name for what was known in Turkey as "Greater Syria," which included Syria plus Lebanon, Israel, Palestine, and Jordan, more or less. In Arabic the name for this, which gives the "SH" at the end of "DAEESH," is "al-Sham," which is indeed a much older name for the area, dating back at least to the Ummayyad Caliphate, 661-750, which had its capital in Damascus, the current capital of what is left of Syria. So, "ISIS" is better than "ISIL," as it can stand for "Islamic State of Iraq and al-Sham."
So, I do want to disabuse two more distorted ideas floating around, namely that this state ist a nascent "Caliphate," something that is being widely repeated, including in two front page stories today in the Washington Post, and that it was thrown out of al Qaeda for being more violent than al Qaeda's leadership approves of. The latter is easily dismissed. Zawahiri disowned DAEESH because he backs another Islamist opposition group in Syria, Nushrat, and is angry that DAEESH has defeated them and is now the main group and is not following his orders. It had nothing to do with them being more violent than the group he backs or any other group he backs, pretty much all of which are violent. It is simply a matter of turf and control, and the leader of DAEESH, the somewhat mysterious Abu Bakr al-Baghdadi, does not take orders from him.
BTW, just for the record, DAEESH is clearly very violent and also very fundamentalist, although I have not heard that they forbid women from driving as is done in our ally, Saudi Arabia.
But let us deal with this matter of whether or not this neo-Zengist state is a "wannabe Caliphate." Now, I cannot prove that it is not. But the evidence that it is turns out to be mostly coming from flamingly neocon sources. If one pushes into Arab sources, there is no evidence of this, and the most one can do is make inferences from scattered pieces of evidence. Officially, al-Baghdadi has been "Amir al-Hakim," Ruling Emir, the same title that Mullah Omar had in the Taliban regime, which may be more of a model. A Ruling Emir does have authority over religious matters, but is far from being a Caliph, or Khalifa (with a Caliphate being a Khilafa). Now, al-Baghdadi has just turned this over to another person, so maybe he is about to declare himself Khalifa, but he most definitely has not done so up until now, so most of the discussion of this in the western media is wildly wrong. The strongest argument that he might do so is that this name he took, which is a nom de guerre, includes "Abu Bakr," who was the first Caliph. So, maybe, but not yet.
What does it mean to be Khalifa? The term means a lot of things, including Successor, Servant, Viceroy, and some others. Traditionally a Caliph is supposed to be the Successor to the Prophet Muhammed as the spiritual and political leader of the Ummah, the world Islamic community (the word "Umm" means "mother"). Following the Prophet's death, he was succeeded by four such Caliphs, his uncle Abu Bakr, Umar, Uthmann, and Ali, his son-in-law, these known as the "Rashidun" or "righteous" Caliphs. After Ali's death came the Sunni-Shi'i split with the Shi'is supporting Hasan, Ali's son by Fatima, the daughter of the Prophet, but Muawiyah of the family of Uthmann defeated and killed him and became the next Caliph, establisling the Ummayyad Caliphate that would rule from Damascus until 750. During this period it expanded control from Spain to Central Asia. It would be succeeded by the Abbasid Caliphate, that ruled mostly from Baghdad from 751 until being overthrown by the Mongols in 1258. There was a rival Fatimid Shi'i Caliph in Cairo from about 900-1100, one of whom burned the Church of the Holy Sepulchre in Jerusalem, providing the official cause d'etre of the Crusades. There was a "Shadow Caliphate" run by Abbasids in Cairo after the fall of Baghdad, but then the Caliphate was taken over by the Sultans of the Ottoman Empire after the fall of Constantinople in 1453, who would hold it until it was abolished in 1924 by Ataturk. There was a brief effort to claim it then by Sharif Hussein a-Hashim, the traditional ruler of Mecca and a descendant of of the Prophet, but in 1925, King Abdul-aziz (aka "Ibn Sa'ud") roared out of the desert from Riyadh and threw him out for being a total sinner. He did not take the title, which has remained unclaimed except by occasional oddballs, although the Saudi kings are most proud of being "Protectors of the Holy Cities," meaning Mecca and Medina. The British would reward the Hashemite Sharif for his loss by making his sons kings of Jordan (Abdullah I) and of Iraq (Faisal I) respectively, with that family still ruling Jordan under Abdullah II.
I note that the word shows up in other places. So there are regional officials in Morocco who carry the title of "Khalifa," but there it means "viceroy" or "governor." The Shi'a have mostly substituted "Imam" for it, but the 7-Imam Shi'i, the Zaydi, of northern Yemen, called their leaders by the title until 1962. And the royal family of Bahrain, Sunnis ruling over a Shi'i majority, happen to be named "al-Khalifa."
Anyway, certainly DAEESH or ISIS or whatever is a nasty violent bunch pushing a hardline version of the Shari'a and would like to conquer at least Iraq, or at least Baghdad. But there is little evidence that they are a "wannabe Caliph" from serious sources, with this mostly a neocon myth perpetrated successfully in the gullible and ignorant western media, although it cannot be ruled out that Abu-Bakr al-Baghdadi might just declare himself this title. But he has not done so yet, contrary to widespread impressions.