Iraq has never been a country on its own and has only acted as one since WWI when it was patched together by the British to deprive Turkey of oil fields. Saddam Hussein and his minority Sunni Moslems fell; the Shia Moslem majority has used its ascension to government against the Sunnis and the non-Arab Kurds want freedom from both. And now, the non-Arab Iranians are helping their fellow Shia by sending forces to Iraq. This is a nest of snakes.
Iranians historically feel entitled to dominate Arabs, who disagree. Sunni Arab conservatives see Shia, whether Arab or Iranian, as heretics deserving of death. And some 30 million Kurds overlapping Iraq, Iran, Syria and Turkey think they are entitled to their own country and the oilfields it holds.
The Bush/Obama invasion removed the bottle cork holding all this static –Saddam Hussein — and put it into play. Now the pieces are sorting themselves out. The appearance just now is that the U.S. wants Iraq held together. The Kurds, likely supported by Israel, want to tear themselves and their oil, loose. And the Sunnis want loose from the Shia, plus they want Bagdad. Exactly what the Iranians want is unstated, but they have traditionally wanted hegemony over Arabs.
The Kurds are now de facto loose from Iraq. The rest is unsettled, but the Shia government is getting support from Europe and the U.S. as well as from Iran. Even the Sunni Saudis seem to be helping that. That has to lower the prospects for the Sunni ISIS rebellion in Iraq.
The Kurds future is uncertain; All the countries they straddle have found them troublesome and desirous of independence. Their oil is envied as well. And their Peshmerga is one of the beter military units in the region.
All these willful pieces have self-disassembled like a regional Humpty-Dumpty. All the kings’ horses nor all the kings’ men are available; can U.S. Secretary of State Kerry put this back together again? Can his boss? Will the Kurds end independent with their oil? Stay tuned … (A hint: The Kurds are driving the Arabs nuts by breaking an Arab taboo: selling oil to Israel, apparently with Turkish unconcern.)