I think the increase in violence is more due to increasing tension between the Sunnis and Shiites. I just read an article that said 50 people were killed across Iraq yesterday and that there are concerns about the Sunnis raising an army to defend themselves from being politically marginalized.
I don't think American troops could've helped much with more people there. We just would've had more fatalities and citizens here would've looked at Iraqis as the villains. I am glad we have decreased numbers there because I prefer not to have American casualities in such a hotbed for violence, like Iraq.