Is Iraq really ready to protect itself without direct American military support?
I have to wonder where you're getting your information from, as a February 23 article from this year has stated insurgent violence has hit an all time low since 2003. See source:
http://www.army.com/news/item/4857 Has the violence risen that dramatically since then?
In all honesty, I think the sooner we can withdraw, the better. Prolonged military presence past a point where we're needed isn't likely to help matters. It'll probably end up being a sink or swim situation for Iraq no matter when we leave.
Also, an interesting thing to note, while violence has been decreasing in Iraq, the violence in Afghanistan has been increasing, despite the increase in soldiers. I get the feeling that this whole "War on Terror" thing is just a endless game of cat and mouse that no one will ever win.