A surge in violence in Baghdad has prompted fears that Iraq may be on the verge of a new spasm of sectarian violence. Many think the attacks are intended to sew doubts about the wisdom of the upcoming withdrawal of U.S. forces from Iraq. By this logic, the bombings are intended to force the U.S. to stay on with the implication that the government of Prime Minister Nouri al-Maliki is weak and that he is merely an American puppet.

April was one of the bloodiest months in Iraq in years. According to one estimate, over 450 people were killed in political violence last month, up from 335 in March, 228 in February and 242 in January. In Baghdad alone, more than 200 people were killed, more than double the number of March, and four times the casualties of February. In one 24-hour period, 160 people were killed. Those attacks are especially worrying because they demonstrate a frightening vulnerability in the heart of the country.

Most of the attacks target Shiite civilians, the majority of the population in Iraq. This raises fears that a Sunni insurgency is launching a new campaign. Sunnis are angry that they no longer control the levers of power in Iraq as they did during the Saddam Hussein years. Their anger at being displaced has fueled numerous insurgencies since the fall of that odious regime. The readiness of many Shiites to take revenge for the injustices they suffered during that time has only increased Sunni resentments. As the wheel of retribution turns, the country totters on the brink of a descent in to sectarian violence.