A political as well as a military quagmire.

The Shia clerics will want to retain UK military presence until their power has been guaranteed by adoption of the new constitution.
Then the real trouble will start.

As I said long ago the Iraqi elections have much more to do with factional power than democracy.

There seems to be no end to the short sightedness of the people who started this conflict. Other posters have remarked on the short term nature of Western political thought, and in Iraq they have been proved correct time and again.