This isn't surprising. In his July report on the state of Iraq, Stuart Bowen, the special inspector general for Iraq reconstruction, had this to say: "Iraq remains an extraordinarily dangerous place to work. It is less safe, in my judgment, than 12 months ago." Bowen writes that Iraq is still struggling to protect judges and officials from assassination and that the security "situation continues to deteriorate."
News coverage has included the by now obligatory-hand wringing over whether Iraqi security forces are up to the job. The New York Times says that "the violence raised significant questions about the capabilities of the Iraqi security forces." The Washington Post writes "they also raise questions about the Iraqi government’s ability to maintain security as American troops prepare to leave the country by December."
This is journalese. "Questions" aren't really being raised. It's evident that the ability of Iraq's security forces to end militant violence by force alone is nonexistent. The reason why is that the number of people willing to engage in attacks isn't small enough yet, that a substantial portion of the population looks at the Shiite-dominated government with sufficient suspicion to provide passive support to the fighting (by, say, deciding not to inform security forces of a neighbor who appears to be building a bomb in his garage), and that fighters – whether Sunni insurgents or Shiite militants that the US alleges are receiving support from Iran – still believe there's power and influence to be won at the end of a gun.