I agree, only time will tell. However, "vowed" and "by the end of this year" is a timetable.
This is a WAR. Not a PR battle. Even if this were the plan "all along" why divulge it to the world and your enemies? It does NOT make sense!
I would not be surprised if the attacks started to wain. And I would not be surprised if they wain because the instigators see a misstep, a weakness in resolve. "By the end of the year" is less than a year away.
If I were an insurgent, terrorist or an instigator of an Iraqi civil war, I would tell my troops: "There it is, my brothers. A timetable. Back off. Let the Americans believe the Iraqi "troops" are in control. Be patient. It will only be a matter of time now when the Americans leave and we can continue."