(1) U.S. military occupation continues into the indefinite future. Eventually, guerrilla warfare to oust the American occupier re-emerges. The U.S. military administration becomes the main source of recruitment for jihadis.
(2) Chalabi, or someone like him, emerges as the Iraqi Karzai, a puppet who can't move around the country without U.S. military escort, while real power devolves to regional warlords. Scaled back U.S. military occupation focuses on controlling the oil fields (which have probably been privatized...Amity Shlaes was used to run up a trial balloon for this plan in FT about a week ago). Conflict with Iran becomes more and more possible as Iran seeks to extend its influence in Shia regions.
(3) The "democratic imperialists" like Wolfowitz turn to be out as they advertise themselves, get their way, and install a formally democratic regime in Iraq. With or without a Kurdish breakaway, this state will have a pronounced Shia majority. Two possibilities present themselves: (3a) A Shia party aligned with Iran emerges as the dominant political force in this new democracy. Washington "discovers" that Iran is much closer to possessing nuclear weapons than Iraq ever was, and contemplates an Iran-Iraq alliance in the Gulf that threatens to become the regional hegemon. (3b) Confessionalism turns out not to be the dominant political cleavage in Iraq, and a democratic Iraq faces a nuclear-arming Iran that is very willing to try to foster pro-Iranian Shia mobilization within Iraq (democratic or not). In response, a weak threatened Iraqi state finds itself forced to try to match the Iranian arms buildup.
Under either scenario, how long before the "democratic imperialists" decide that the "democratic" part of their imperialism was a bad idea and we're back in again?
Sufficiently depressed? Then let's start thinking seriously about the contradictions of imperialism and how this imperial adventures ends badly for the interests of the empire but well for the interests of Iraqis. Because if we're going to find anything but depression in this turn of events, that's where we're going to have to find it.