An excellent question

Perry de Havilland boils down the big question about Iraq (and Afghanistan):

In both the USA and UK, much of the debate about how to react to the military situation in Iraq really strikes me as really odd. If a person thinks the available facts indicate we are not doing well against the insurgents, surely the choices should be either:

1. Conclude the enemy will inevitably win and no military and political victory is feasible, therefore accept being defeated and get out completely as soon as possible
2. Conclude the enemy can be beaten, but not at an acceptable cost, so accept being defeated and get out completely as soon as possible
3. Conclude the enemy can be beaten and therefore reinforce to improve the military force levels (i.e. the 'Surge') in order to actually win

What does not make any sense to me is any talk of reducing force levels by a person who does not think we have either already won or already been irretrievably defeated . . . and the stated position of most politicos on both sides of the Atlantic is neither of those things.

It's only a quagmire if you choose to make it one. Sending enough forces to do the job (however you define "the job") is the only sensible way to operate. Sending insufficient forces just means that success must be defined down to fit what is possible with the forces you sent. Demanding that they accomplish more than is possible is just plain delusional.