In the once-turbulent Sunni enclave of Adhamiya, hope that the elections Sunday will herald a dramatic change in Iraq’s leadership mingles ominously with fear that it won’t.

There’s none of the reluctance that characterized the last elections in December 2005, when a boycott call from Sunni Arab leaders and the ubiquitous presence of insurgents deterred most people from going to the polls, and candidates didn’t dare campaign for fear of being killed.

This time, huge billboards promoting Sunni and secular candidates jostle for attention on drab streets strewn with garbage. Top politicians, including Sunni Vice President Tariq Hashimi and former Prime Minister Iyad Allawi, have made campaign appearances, mingling with citizens in markets, kissing babies and urging everyone to vote.

Everyone, it seems, says they will.

And expectations are high -- perhaps dangerously so -- that the full participation of the Sunni Arab minority will bring to an end five years of rule by the Shiite Muslim religious parties that took power after the U.S.-led invasion in 2003.

“This election will bring change,” said Abdullah Sabah, 26, a businessman who plans to vote for Allawi and has no doubt that he will win. “He will create equality among Iraqis because he is not sectarian, which means opportunities and jobs will be available to us.”

Allawi, a secular Shiite whose Iraqiya coalition includes both Sunnis and Shiites, seems to be the preferred choice of most of the voters in this staunchly Sunni Arab neighborhood, a sign that politics have matured somewhat since the days when this was a stronghold of the Sunni extremist group Al Qaeda in Iraq, and Shiites, a minority in Adhamiya, were driven from their homes or killed.

How much politics have matured, however, is the fundamental question confronting Iraq as it prepares to elect a government that will steer the country beyond the planned final departure of U.S. combat troops by the end of August and all U.S. forces by the end of 2011.

The 2005 vote was followed by a civil war in which triumphalist Shiites leveraged their control over the institutions of state, including the security forces, against Sunni insurgents, who fought a government they didn’t choose.

These elections, with their multiple competing factions and massively uncertain outcome, have the potential to be just as destabilizing, said Joost Hiltermann of the International Crisis Group.

“Whether the results alone will trigger a renewal of conflict, I don’t know. But it’s not clear whether the losers, whoever they are, will accept defeat,” he said. “Anything could happen, and it will be happening just as U.S. troops withdraw.”

Across the street from Adhamiya’s Abu Hanifa mosque, once the scene of fiery anti-U.S. sermons and frequent attacks on U.S. forces, men gathering at a tea shop spoke darkly of renewed conflict should the same Shiite parties win.

They are convinced that full Sunni participation at the polls will bring a new government to power, headed by Allawi or by another secular or a Sunni leader.

They say they are not prepared to contemplate the alternative, a renewed mandate for the Shiite religious parties, be it Prime Minister Nouri Maliki’s State of Law coalition or the Iraqi National Alliance.

“Don’t tell me that they will win. They will not win,” said Khalil Ibrahim Rasheed, 42, who is a member of the local Sunni Awakening force, made up mostly of former insurgents who helped the United States drive Al Qaeda in Iraq-linked extremists out in 2007. “If it happens that they do, we will give victory to the one who deserves it by force. We are prepared to die for our religion and our country.”

Such talk may be bravado. In the battle for control of Baghdad’s streets that raged in 2006 and ’07, Sunnis lost. Driven out of many once-mixed neighborhoods, they are now confined to a few enclaves scattered across the city. Adhamiya is surrounded by a 15-foot concrete wall, installed to keep insurgents in as well as Shiite militias out, and residents say they feel nervous every time they venture out into the majority Shiite city beyond.

Fears arose about Sunni participation after nearly 500 mostly Sunni and secular candidates were barred from running because of alleged ties to the former Baath Party. U.S. officials say they are encouraged that it did not lead to any significant calls for a Sunni boycott. But the ban could fuel Sunni complaints of unfairness should the election not go their way, and it has heightened the Sunnis’ sense of alienation from a government perceived as prejudiced against them.

“It makes them feel insecure,” said Maysoon Damluji, a spokeswoman for Allawi’s coalition.

Insecurity underpins the determination of Sunnis here to vote. They complain of persecution, of arbitrary arrests and detentions, of discrimination in the job market. Adhamiya gets fewer hours of electricity than other neighborhoods, garbage is rarely collected and reconstruction projects are virtually nonexistent, they say.

“This government has created an imbalance,” said Abu Adil, 70, whose two sons have been detained without being charged for more than a year by the Iraqi security forces. “If balance is not restored, there will be many problems between the government and the people.”

It’s a prospect that worries Khaled Qassem, 33, a former soldier who lost his job when the U.S. disbanded Saddam Hussein’s army in 2003. His brother was killed in sectarian violence in 2006. Qassem now supports his brother’s seven children and his own year-old baby on his meager earnings as a taxi driver. He confides that his mother is Shiite, and he sometimes visits his Shiite relatives just across the Tigris River that splits the capital, in the rival neighborhood of Kadhimiya.

“They are like us,” he said of the Shiites there. “They complain of the same suffering as us. Every household, on both sides, lost someone to the fighting. If we fight again, only women and children will remain, and who will be left to support them then?”

But Qassem says he’s confident there won’t be another war.

“I have this very strong feeling, deep inside my heart, that this election will change everything,” he said, patting his chest and grinning broadly.

liz.sly@latimes.com

Times staff writer Raheem Salman contributed to this report.