Wait until 0 troops are left? A calculus for Iraq War supporters

Let me pose a calculus that should have nothing to do with how anyone perceives reality. It is just an exercise that anyone can take and use. My hypothetical situation could be wrong. Maybe you think the outlook in Iraq is still bright and will continue to improve. If so, I still ask that you humor me below.

IF no (or any more than, say 10,000) troops were to be added to Iraq, and

IF the death rate of both Iraqi civilians and US troops were increasing,

IF, at x months from now, the outlook regarding Iraq’s stability or ability to police itself were to be poorer than whatever you think it is now,

then should the US ever pull out? Again, I’m talking hypothetically.

If you think that no, the US should not pull out (and note that this is the current public policy of the Bush Administration: no troop withdrawal and no increase in troop levels), then there’s an absolute limit to the number of US troops who can remain in Iraq: 0.

This would mean that all troops currently serving in Iraq would be dead or captured (or deserted or whatever). Do you believe that the US should wait until 0 US servicepeople remain in Iraq?