What If We Had Left Iraq?

Matthew Yglesias suggests that 2005 would have been the perfect time to leave Iraq:

Instead, the reason given for why we had to stay in Iraq was that if we left Iraq there would be civil war, sectarian violence, and ethnic cleansing. Since we know all of that happened anyway it seems reasonable to second guess the decision-making that led us to stay.

Deaths per day in Iraq from suicide attacks and vehicle bombs by year:




Deaths per day in Iraq from gunfire and executions by year:




Of course, it can be argued that these violence levels would have been even worse without the U.S. presence, but it's hardly clear that staying through 2006 and 2007 accomplished our goals.