Ok, I guess people already marked me as a damn Canadian Liberal (even if I resent that), but I still hope I do not score as low as a certain Colonel and you still read me

Morality aside what is happening in Iraq. When you put aside whatever political goals, morale, national security, etc... All these REASONS to stay are already debated hotly in 10000 other threads, so let's ignore them - for now -.
What would HAPPEN if the troops stay longer (and by "longer", I mean another 3-5 yeasr)? Let's ignore the speculations for a second (what we don'T know for sure what will happen), and talk about what will happen for sure:
1) U.S.A.'s military spending are going to skyrocket. With the actual economical slowing the U.S. is suffering (I don'T think someone can really argue against that), the USA are less likely to have their income increase in the near future. But the more you keep you 130 000 troopers in Iraq (+ uncounted and hidden number of mercenaries), the costlier is going to be.
Personnally, I don'T think the USA can afford such expense on the long run. The baby-boomers will retire in the following years, and Asia&Europe competition is getting stronger every year. The last thing your country needs is a large-scale money sink.
2) U.S. Troopers will continue spending 55% of their active duties on the field.
About a few months ago, I've seen in The Economist that British Troops spend 20% of their duties on field duty, and with a British General's comment that this is almost the upper limit their troops should healthily be used.
The American Army's regular trooper spend more than double that. Statisticly, he spends more than half his duty time on field duty.
On the long run, that can be disastrous for the morale of your army. For it's moral as well as it's efficiency, it's professionnalism.
And the more time it spends in a dangerous environnement, the more likely they will - accidently - do mistakes making them ever and ever more unpopular at home. We don't need another vietnam, with other veterans who come home and being spitted at.
Even BEFORE the Dems took the house, the American army was over-extend and over-used (infantry-wise, off course).
I think people should stop using cheap tricks that "you don't support our troops" when Dems want to cut funding. I say the previous congress wasn'T really respecting them either, if the situation has come to this.