The attacks appeared to be a well-coordinated assault by Sunni militants linked to al-Qaida and targeted markets, grocery stores, cafes and government buildings in a dozen neighborhoods. They coincided with a government crisis that has already strained ties between the two sects to the breaking point.
For many Iraqis, this could be the beginning of a nightmare scenario: The fragile alliance in the governing coalition is collapsing, large-scale violence bearing the hallmarks of al-Qaida insurgents has returned and Shiite Prime Minister Nouri al-Maliki may be moving to grab the already limited power of the minority Sunnis.
"The conditions that perpetuate civil wars are making a hasty comeback," said Ramzy Mardini, an analyst at the Institute for the Study of War in Washington.
The bombings may be linked more to the withdrawal of the last U.S. troops Sunday than the political crisis, but all together the developments raise the specter of a return to the Shiite-Sunni sectarian bloodshed that pushed Iraq to the brink of civil war in 2006 and 2007.