The ‘surge’ and the switch to more determined counterinsurgency tactics (putting small garrisons of American soldiers throughout Baghdad to act as police forces, regular patrolling) was always going to cause higher casualties (more vulnerable locations, patrolling=targets) and that’s been borne out so far:
Deaths per day for March were 2.65
Deaths per day for April (so far): 4.06
The hoped for pay-off would be a more peaceful Baghdad. At the start, that did seem to happen. Sectarian violence, as best I can tell, dropped substantially in the early weeks. But, of course, war is about action and reaction and counter-reaction. The insurgency responded by ramping up the number of suicide bombers, including the concerted attack this week:
The goal here is obvious: demonstrate clearly to the population of Baghdad that the United States cannot guarantee their security.
The other reaction has been to shift attacks from Baghdad to other areas of Iraq. Thus, in Tal Afar, for example, insurgent attacks have increased. The problem, from the American perspective, is the same: not enough troops to shift to hot spots, and a lack of effective Iraqi forces to take up the burden. The American counter-reaction would be (in addition to adding troops in the hot spots) to try and cut off the supply routes of the insurgencies (ie into Syria and Iran) but that’s not possbile without more troops.