Two large bomb blasts in Baghdad, one aimed at the Foreign and Finance Ministries, killed at least 100 people and injured about 600, putting something of an exclamation point on a month of escalating insurgent violence and calling into question the capacity of the Iraqi government to provide effective security. There will be those who urge the United States, which pulled out of Iraqi cities June 30, to deploy some troops back into the cities, if only temporarily, to get the insurgent violence under control. This is unlikely, and it would be unwise.

There is little question that the record of the Iraqi government since the U.S. withdrawal from cities has been spotty. Despite persistent pressure, Prime Minister Maliki's Shia-dominated government has dragged its feet about giving Sunni Iraqis (including fighters in the Anbar Awakening who turned on al-Qaida and turned around a deteriorating situation) positions of genuine authority in the government and security forces. Although no one has yet taken "credit" for Wednesday's bombings, most observers believe they were done by Sunni militants.

In the northern city of Kirkuk, oil-rich and on an uneasy boundary between traditionally Arab and traditionally Kurdish areas, tension between Kurds and Arabs is mounting, 140 people have been killed since July 1, and some American forces will be deployed.

The violence has not yet risen to the level of being a civil war, but it is more than a little troubling. If Sunni Arabs who dominated government under Saddam Hussein but have seen their power dwindle because they are a minority in Iraq as presently constituted come to believe there is no hope they will get a fair shake (read: a share of oil revenue) from the central government or from the Kurds, an increasing number could decide that armed resistance is their best hope.

These are difficult problems, but whatever responsibility the United States might bear for having unleashed hostilities that Saddam Hussein had cruelly kept in check through state violence, they are now the Iraqis' problems. They will undoubtedly make mistakes along the way, but based on the record there is little evidence that the U.S. could fix things by sending troops back into the cities on a temporary basis. Our time there is over.