BAGHDAD  Shiite clerics and politicians have been successfully urging their followers not to retaliate against a fierce campaign of sectarian bombings, in which Shiites have accounted for most of the 566 Iraqis killed since American troops pulled out of Iraq’s cities on June 30.

“Let them kill us,” said Sheik Khudair al-Allawi, the imam of a mosque bombed recently. “It’s a waste of their time. The sectarian card is an old card and no one is going to play it anymore. We know what they want, and we’ll just be patient. But they will all go to hell.”

The patience of the Shiites today is in extraordinary contrast to Iraq’s recent past. With a demographic majority of 60 percent and control of the government, power is theirs for the first time in a thousand years. Going back to sectarian war is, as both Sunni extremists and Shiite victims know, the one way they could lose all that, especially if they were to drag their Sunni Arab neighbors into a messy regional conflict.

It is a far cry from 2006, when a bomb set off at the sacred Shiite shrine in Samarra killed no one, but ignited a fury at the sacrilege that set off two years of sectarian warfare.