Afghanistan's (search) first direct presidential election Saturday will be a historic experiment with democracy after more than two decades of ruin, from Soviet occupation to civil war to the repressive Taliban and the thunderous U.S. bombing campaign that ended their rule.

Despite persistent violence from still-vigorous Taliban (search) insurgents, the United Nations (search) has declared this hard-luck nation ready for the vote, following a campaign that focused on tackling feuding factions and helping people out of poverty.

Thousands of polling stations manned by hastily trained staff open early Saturday for some 10.5 million Afghans who registered for the landmark vote. It will be closely watched by American, NATO and Afghan security forces.

Interim leader Hamid Karzai, seen by many Afghans as a bridge to the West and a figure unsullied by the country's long-running strife, is expected to garner the most votes and secure a five-year term. Partial results are expected by midweek.

But there are serious doubts about the integrity of the country's fledgling democracy amid sustained violence and evidence that officials have abused their office to help the U.S.-backed incumbent.

"Peace will not come until the Afghans see that their rights are being observed," said Yusuf Pashtun, the governor of Kandahar province, once the capital of the Taliban regime and home to Osama bin Laden.

Campaigning ended Wednesday with a burst of violence when attackers set off a bomb near a convoy carrying Karzai's vice presidential running mate in Badakhshan province. Ahmed Zia Massood wasn't hurt, but one person was killed and four others wounded.

Karzai, the overwhelming favorite among the 18 contenders, has said Saturday's election is an opportunity to build a new future for a country that has known nothing but war, drought and poverty for a quarter century.

The vote is a key step in rebuilding an Afghan society following decades of turbulence, with the Soviet invasion of 1979, the 1985-89 war against the occupiers, the ruinous 1992-96 civil war that ended with a Taliban victory, and the U.S. campaign to oust them in late 2001.

Karzai's opponents include warlord chieftains of Afghanistan's northern minorities to a relative of the country's last king and a former U.N. worker running as the only female candidate.

The breadth of the field could scatter votes so widely that Karzai fails to achieve the majority needed to avert a run-off, which would give Taliban rebels another chance to disrupt Afghanistan's democratic process. At least a dozen election workers have died so far in a string of attacks, while Karzai and two his closest aides survived rocket and bomb attacks during the campaign.

While Karzai has won endorsements from regional leaders across the country's deep ethnic divides, many of his fellow ethnic Pashtuns have not registered in the south because of insecurity, while conservative custom has kept many women from signing up.

Drug smugglers and disgruntled militia forces who helped the U.S. military oust the Taliban three years ago but are now set for disarmament under a U.N.-backed peace plan also may have reason to disrupt the vote.

Still, the American military sees the election as an opportunity for the militants and Karzai's internationally backed transitional government to seek reconciliation.

Some 18,000 U.S.-led troops are in Afghanistan, up from just 11,000 late last year, to help protect the vote. Another 9,000 NATO-commanded soldiers are on the lookout for trouble in the capital, Kabul, and much of the north.

"Now, are they (the polls) going to be perfect? No. Are they going to be marred by violence? Yes. But we are seeing things happening now that we couldn't imagine a year ago, or two years ago, and certainly not around 9/11," said Maj. Gen. Eric Olson, the No. 2 U.S. commander in Afghanistan.

Even if the vote goes ahead without major violence, a Karzai victory is sure to draw criticism that the incumbent benefited from a campaign that flouted the country's election laws.

Former Kandahar Gov. Gul Agha Sherzai, a powerful tribal leader now serving in Karzai's Cabinet, told hundreds of elders on Tuesday to vote for Karzai, even though the rules say all officials have to remain neutral.

Ahmed Wali Karzai, the president's brother who has marshaled his campaign in the south, shrugged, saying Afghans would not understand why a tribal leader should hold his tongue.

"Democracy is a baby in Afghanistan," he said.