Surprised at just having read an article on AlJazeera arguing that far from being by and large a failure, US involvement in Iraq has actually been a resounding success on the grounds that the intention all along was to split the country along sectarian lines. This seems ridiculously counter intuitive.
Dismembering the body politic in Iraq
http://english.aljazeera.net/NR/exeres/7DFA2889-95A5-4B0A-A767-14E1A93C2539.htm
1) I had gained the impression that part of the point was to build a friendly, pliant state for several purposes - namely oil extraction (Iraq being ranked around 4th in oil reserves), to gain a 2nd extended millitary base/ally (besides Israel) in the region and to gain some sort of PR victory.
1) Turkey. Turkey could not tolerate an independant Kurdish state on its southern border with its already seperatist (and large) Kurdish minority. Such a challenge would inflame the already simmering tension between secular state and army and the growing power of faith based politics.
3) If Iraq were to split into three, besides the destabilising influence of an independent Kurdish entity the Shia and Sunni areas would surely, having turned to religion as a prime source of ethnic identity be likely to gravitate toward the spheres of influence of their respective ethnicities. In the case of the Shia population this would obviously be Iran. And with the more diffuse Sunni identity who knows, but in some cases might adopt bin laden style ideology.
The US seems to have nothing to gain and everything to lose from a messy three way split in Iraq. So no its not working and they've screwed up really bad.