While we're at it, what was al-Maliki doing very, very wrong? He was keeping Sunnis out of the government, keeping almost the entire government Shi'a, and we and other nations told him that he was screwing up by doing so. Before we left Iraq, we had his agreement to include Sunnis in the government that they, too, would have representation. al-Maliki didn't do it. We warned him that this would lead to unrest among the Sunnis, and he did not listen.
I suggest you determine who really was at fault for the Sunni unrest before you start blaming everything on Obama.