The surge in adopting a primary identification as “Iraqi” among Iraqi Arabs is very interesting and it seems plausible to speculate that this played a role in the declining level of sectarian violence starting in the latter half of 2007. Alternatively, it may have been caused by the spike in violence seen during 2006 and early 2007 that may have launched an anti-sectarian backlash.
But Iraqi Kurds evidently have a very different relationship with Iraqi identity than do Iraqi Arabs. The issue of Kurdish independence has stayed quiet, with the Kurds too prudent to do anything unduly provocative and the Iraqi state too weak to make any effort to actually govern in Kurdistan. But the better things get in Iraq, the more these sorts of issues will come to the forefront.