TEHRAN, June 23 - The biggest surprise of last week's presidential contest was the emergence of the little-known mayor of Tehran as the second highest vote getter, putting him in Friday's runoff election. That has led to widespread charges of vote rigging and a systematic, organized conspiracy to alter the outcome.

Yet conversations with a Western diplomat and a broad spectrum of Iranians suggest that the charges are overstated.

There does seem to have been an organized effort among military and religious leaders to put pressure on voters to back their candidates. But what really has people outraged is that the insurgent candidate, Mahmoud Ahmadinejad, who is 49 and not part of the political elite in Iran, has bucked the established order by running a most effective campaign.

Many people fear Mr. Ahmadinejad because his social and economic ideas are a throwback to the early days of the revolution. But others simply cannot believe that a man who has not been part of the political elite might leapfrog over elder statesmen of the country to take power. In one piece of campaign literature, Ali Akbar Hashemi Rafsanjani, the other presidential candidate, simply lists his résumé side by side with Mr. Ahmadinejad's, as though nothing more need be said.

Despite the claims of vote fraud, there was no investigation; the appointed religious officials simply dismissed the charges. But critics have not presented any evidence, and instead have talked about unfair and inappropriate influence peddling.

"Military commanders gave talks and encouraged people to vote a certain way," said Mehdi Karroubi, a former speaker of Parliament and candidate for president who created a scandal here when he charged vote rigging in the first round. "We have evidence that the Basiji and military were interfering with the vote." The Basiji are volunteer militia members, some of whom enforce Islamic rules by beating demonstrators and whipping women who do not conform to religious dress codes.

He added, "Basiji are inspectors at polling places and have power to do a lot of things."

What things? Mr. Karroubi did not say.

Instead, like many critics of the first round, he pointed to the numbers as proof that something must have gone wrong. For instance, how could a man like Mr. Ahmadinejad, largely unknown outside Tehran, manage to win 800,000 votes in Isfahan, the hometown of another candidate?

It is a charge that has been repeated over and over, but to date has not been examined. But news reports in the Iranian newspaper that covered Mr. Ahmadinejad's trip to Isfahan this month reported that thousands of people had welcomed him in the streets. The report further said that Mr. Ahmadinejad's plane had been hours late, and that still the crowd had waited - demonstrating, at least, some degree of support.

A Western diplomat, who was preparing an analysis of the vote for his home office, said it did not appear that a huge, systemic fraud had occurred. The diplomat spoke on the condition of anonymity so as not to offend anyone in the government.

The diplomat said the country was too large, and the electorate too diverse, for anyone to orchestrate widespread fraud. He said many of the voting patterns that emerged, like most of the candidates' winning in their home provinces, made sense.

The diplomat noted, for example, that Mr. Rafsanjani came in first place in only three provinces but took second place in 19 provinces, another figure that seemed to make sense for a candidate whose support is wide, but not considered very deep.

But the diplomat also noted that with seven candidates in the race - an eighth dropped out in the final stages - it was necessary to manipulate only a few hundred thousand votes to change the outcome. And that, he said, also appeared possible.

More than that, there is undeniably a culture of leverage politics here where people with political, religious or economic influence use it to lean on others to vote a certain way. The effect of that kind of pressure can be insidious in a society where fear is a tool of the ruling class and where challenging those in power can come at a price.

Hamed Salamati, a Basiji member in Tehran, said he doubted that there had been any actual vote tampering. But he confirmed that the militia's leaders and hard-line clerics had tried to use all their influence to push the vote in the direction they wanted.

He pointed to a dawn prayer session this week for Fatimah, one of the Prophet Muhammad's three daughters. Every year worshipers mourn her death, and a crowd had assembled in Tehran to listen, quietly, to the singing of the dirge, a mournful remembrance of Fatimah.

Suddenly, the person singing broke into a political diatribe, he said, telling the worshipers to vote for Mr. Ahmadinejad, while railing against Mr. Rafsanjani.

"He used very foul language against Rafsanjani," Mr. Salamati said.

He also said commanders of the Revolutionary Guard had sent a letter to its members, and to Basiji, ordering them to vote for Muhammad Baqer Qalibaf, a former police chief who ended up in fourth place. But he said Basiji preferred to follow the lead of high-ranking clerics and so voted for Mr. Ahmadinejad, because he was the candidate the hard-line clerics said they should choose.

"The Basijis encouraged their families to vote for Mr. Ahmadinejad, and I think a lot of people voted for him," he said.

Critics have called that inappropriate interference, especially in a society where clerics and the military rule by loyalty and fear. But such pressure politics are not only the province of the conservatives.

Mr. Salamati's great uncle, Hassan, is a baker in Tehran. One day, he said, he went to pick up flour for his business and was given posters of Mr. Rafsanjani to put up in his shop.

He said a member of Parliament, who is often a big supporter of the bakers' union, "told bakers to vote for Rafsanjani, and since he always helps the bakers, most of them did."