With two weeks remaining before national elections and 18 candidates running for president, Afghanistan's capital should be a frenzy of competing campaign rallies, patriotic stump speeches and sloganeering.

Instead, Kabul is holding its breath and waiting for word to emanate from a glittering green mansion in a dusty corner of the city, where an enormous poster of one candidate adorns the entryway, old fighters in fading fatigues embrace on the lawn, and aides with cell phones pace the balconies in intense conversation.

The candidate is Yonus Qanooni, 43, the crisp, bespectacled former education and interior minister and onetime anti-Soviet and anti-Taliban resistance fighter who is viewed as the only serious challenger to President Hamid Karzai in the elections scheduled for Oct. 9.

In a stable democracy, Qanooni and Karzai could square off on election day along with the other candidates, the voters would choose and the nation would accept the results.

But in Afghanistan -- a country that has never elected a president, where ethnic sensitivities remain raw and political scores unsettled after two decades of tumult and bloodshed -- many voters and analysts fear that a ballot-box clash of two titans from rival ethnic groups could bring disaster.

As a result, Qanooni, an ethnic Tajik from the Panjshir Valley and political heir to the slain guerrilla leader Ahmad Shah Massoud, has been under intense pressure to quit the race and form a national unity platform with Karzai, an ethnic Pashtun who has governed under a U.N.-guided process since December 2001.

"We need a strong and legitimate government, but voting won't produce that. There has to be a government of national cooperation," said Fahim Dashti, editor in chief of the Kabul Weekly newspaper. Karzai might receive the more than 50 percent of votes needed to win without a runoff, Dashti said, "but we need a government with 75 percent of the vote or it will not be able to govern."

In the past week, both front-runners have publicly denied they plan to form a coalition. Qanooni, who had been widely expected to announce an agreement, instead delivered a ringing campaign speech at a government forum Tuesday, drawing repeated applause and evoking a new Afghanistan that would be "proud, independent, anti-terror and anti-drugs."

In a recent interview, Qanooni -- who walks with a limp from a 1993 car bombing and holds a degree in Islamic law from Kabul University -- reiterated his determination to see the race through. He said he believed in healthy, nonviolent political competition and would never use ethnicity as a divisive tactic.

"I don't see myself as representing one ethnic group, and I don't think any candidate should," he said, poised and professorial in a blazer and slacks. "Nobody in Afghanistan wants to go back to 1992," when the country imploded in ethnic civil war. "What we need is free and fair elections without threats or fraud. We don't want to kill the baby of democracy on its first day of life."

With his repeated calls for national unity, his civilian persona and his widely praised role in the U.N.-sponsored conference that created Karzai's coalition government after the U.S.-led ouster of the Taliban in 2001, Qanooni would appear to be a natural candidate to bridge Afghanistan's ethnic gaps and appeal to a cross-section of voters.

But his chief constituents are legions of former mujaheddin -- grizzled Muslim militiamen who fought the Soviet army in the 1980s and the Taliban militia in the 1990s. They feel fiercely defensive of their ethnic interests and place in history, and Qanooni has played to their emotions by circulating campaign posters that show Massoud -- who was assassinated on Sept. 9, 2001, by assailants posing as journalists who are believed to have been acting on behalf of al Qaeda -- hovering faintly over his shoulder like an angel.

Moreover, Qanooni has not ventured beyond mujaheddin turf to test his wider popularity. Most other candidates have also stayed close to home, largely for fear of attack from revived Taliban forces and other groups that have vowed to sabotage the vote. Some also fear a hostile reception on rival ethnic turf, or simply lack the means to campaign outside of Kabul.

Instead, Qanooni has been meeting privately with endless groups of militiamen, tribal leaders and advisers in the posh green mansion owned by Basir Salangi, the former Kabul police chief, who is also from the Panjshir Valley. According to participants, most visitors have demanded that Qanooni remain in the race, and he has assured them that he will.

"We came here today to give him our support, because he stood beside us in the jihad," said Abdul Jalil Nawaz, 28, who drove to the house Thursday from Parwan province in a van filled with men wearing old camouflage uniforms. "We want an Islamic government that does not make alliances with foreigners. We are all mujaheddin, and if he leaves the election, we will find another one."

Throughout Parwan, a province north of Kabul that was the scene of heavy fighting for years, former militiamen this week expressed similar sentiments. Some of them named Qanooni as their top choice; others were reticent, saying they would vote for whichever candidate followed Massoud's footsteps or was endorsed by community elders.

"Mr. Qanooni is a teacher and a mujahed, like me, but our main concern is security," said Malim Gul, 54, a grocer and instructor in an Islamic school in the town of Charikar. "We want to see unity, not divisions or fighting. There is a lot of fear here. There are a lot of things I cannot talk about. But I don't care if the president speaks Dari or Pashto. I just want a peaceful and stable country."

Karzai also has spoken repeatedly about the need for national unity -- a euphemism for bargaining with his rivals. He named a brother of Massoud as his running mate in July, and his aides and diplomatic allies have privately urged Qanooni and other candidates to join his government, fearing they would siphon off enough votes to deny Karzai a solid first-round win.

At the same time, Karzai has made several moves that could be interpreted as efforts to woo the Pashtun vote at the expense of broader support. In July he dropped one of his vice presidents, a militia leader from the Panjshir Valley, from his ticket. This month he removed a powerful Tajik governor from his post and freed several controversial Pashtun prisoners who had been handed over by U.S. military authorities .

Some analysts say Afghanistan's electoral system, which limited the official campaign season to one month and prevented political parties from registering candidates, has favored Karzai and worked against a fair vote, exacerbating traditional tendencies to manipulate political exercises and making negotiations necessary to ensure a workable government.

"People have little confidence in the process. There is no serious campaign and no politics of ideas, only of personalities," said Vikram Parekh, an analyst in Kabul with the International Crisis Group, a Brussels-based research organization. "People switch sides with abandon and run for office as a means of leverage. The whole structure is meant to perpetuate political deal-making and discourage competitive electoral politics."

Meanwhile, the initial enthusiasm expressed by many Afghans during the voter registration campaign appears to have given way to a period of anxious waiting. There is little public political debate, and the only indications of an approaching election are campaign posters pasted on walls.

Afghans are increasingly expressing fears that on election day, voters will be attacked at the polls, pressured to vote for certain candidates, and defrauded by multiple voter registrations. Many also are saying that they wish the candidates would relieve the pressure, stop playing games and reach an old-fashioned agreement before Oct. 9.

"The country isn't ready for the pull and push of elections," said Ahmed Wali Massoud, a politician and another brother of Ahmad Shah Massoud, the slain resistance leader. "In our history, changes of regime have often brought coups and revolutions, so people are becoming more worried than excited. If they don't see clear results and meaningful change, they may lose trust in the idea of elections altogether."

Yonus Qanooni, a leading presidential candidate in Oct. 9 elections, campaigns in front of a poster promoting his chief rival, President Hamid Karzai.