If successful, the election will mark the first time Afghans have changed their leader at the polls in modern history, bringing to an end Mr. Karzai’s dozen years in power.
No one expected a quick result, however; with three leading candidates likely to divide up the vote, none was expected to get the necessary 50 percent to win on Saturday, and a runoff election was almost certain; it would likely be held no sooner than May 28, continuing Mr. Karzai’s time in office for another two months at least. Even partial official results were not expected for a week.
With eight candidates in the race, the five minor candidates’ shares of the vote made it even more difficult for any one candidate to reach the 50 percent threshold.
The top three vote-getters are expected to be Ashraf Ghani, 64, a technocrat and former official in Mr. Karzai’s government; Abdullah Abdullah, 53, a former foreign minister who was the second biggest vote-getter against Mr. Karzai in the 2009 election; and Zalmay Rassoul, 70, another former foreign minister, who is the only major candidate with a woman on his ticket as vice-presidential candidate, Habiba Sarobi. Polls showed Mr. Abdullah and Mr. Ghani in the lead, but polling in Afghanistan is notoriously unreliable.
Early in the day, in a high school near the presidential palace, an emotional Mr. Karzai cast his own vote for his successor. “I as a citizen of Afghanistan did this with happiness and pride,” he said afterward.
The streets of the capital were almost entirely devoid of traffic, except for members of the police force and the military, who manned checkpoints every few hundred feet and searched nearly everyone passing by.
Most people walked to vote. Long lines had already formed when polls opened at 7 a.m. in a heavy rain in Kabul.
“People have realized that electing the president is far more important than standing in the rain,” said one voter, Abdullah Abdullah, 24, who had the same name as the candidate he said he was planning to vote for at a Kabul high school polling place.
“Whenever there has been a new king or president, it has been accompanied by death and violence,” said Abdul Wakil Amiri, an attorney who turned out early to vote at a Kabul mosque. “For the first time, we are experiencing democracy.”
To provide security for the voting, the Afghan government mobilized its entire military and police forces, some 350,000 in all, backed up by 53,000 NATO coalition troops – although the Americans and their allies planned to not get directly involved except in case of an extreme emergency.
Authorities did not expect that, however, as the level of violence in the months leading to the voting was much lower than before the last presidential election. This time, the Afghan security forces are nearly twice as large, and the election is being held before the traditional start of the fighting season, both factors that have reduced violence by anywhere from 9 to 25 percent compared to the pre-election period in 2009, according to United Nations officials.
A series of high-profile attacks on foreigners, including the murder of an Associated Press photographer and the wounding of her colleague, created an impression of greater violence, but were also indications that the insurgents did not have as much capacity to strike forcefully during this campaign. They did not manage a single major attack on any campaign event, for instance, and two attacks on the Independent Election Commission had little direct effect on the voting.
In the days before the voting, only one policeman was killed in attacks on convoys of election officials delivering materials, in Logar Province, according to the Afghan military. On election day, a bomb set off at a polling place in Mohammad Agha district of Logar injured four voters, while in Baraki Barak district voters complained that Taliban were in the streets preventing people from voting, Afghan officials said.
Even before the voting began, the authorities had already closed 750 polling centers, just over 10 percent of the total, because of security concerns, and there were fears more would be closed on election day. Just how many would likely be a key issue in the aftermath of the voting, especially if closures were seen as disenfranchising one ethnic group over another.
Along with the threat of violence, the legacy of fraud from past elections cast a long shadow over Saturday’s voting. Authorities have gone to unusual extremes to try to guarantee an election at least credible enough to satisfy international donors, who have pledged to continue supporting Afghanistan with billions of dollars in aid, but want to be assured of an election free of the sort of widespread fraud that discredited the 2009 voting.