Many of their senior politicians are tainted with links to Saddam's Baath party.
"They act more on sectarian impulse than political considerations," said a senior Shiite politician Hummam Hammoudi. "They lack a vision for a new Iraq."
Yet, the Sunni Arabs are about 20 percent of the population and are thought to account for the majority in about four of Iraq's 18 provinces.
If they participate in December elections, seats assigned to those provinces could give them 50 to 60 seats in the next 275-seat parliament. That would allow them to form a bloc to be reckoned with and possibly become a desirable partner with secular Shiites, Kurds and nationalists.
"This political process will only succeed when we, the Sunni Arabs, can join a government with nationalist and non-sectarian forces," said Adnan al-Dulaimi, leader of an umbrella of political and tribal groups. "This is what we aspire to."