OSCOW, Jan. 28 — What passes for Russia's presidential contest is progressing smartly.

One candidate has been refused a spot on the ballot, while two others, both businessmen, abruptly withdrew this week with as little fanfare — and clear explanation — as when they entered the race.

Two of the most prominent opposition candidates, Irina M. Khakamada and Sergei Y. Glazyev, have failed to win the backing of their own parties, which instead chose to let their members support the incumbent, Vladimir V. Putin.

Vladimir V. Zhirinovsky, the leader of Russia's nationalist party, who is not running, acknowledged in a television interview last weekend that the party's candidate was a stalking horse who, in the inconceivable event he was elected, would promptly resign and make Mr. Zhirinovsky president.

Mr. Glazyev also came under attack last week on the state's two main television networks, which used hidden cameras to capture what they said were scenes of Mr. Glazyev's supporters in Saratov and Nizhni Novgorod paying for signatures supporting his nomination.

The reports, which Mr. Glazyev denounced as slanderous, prompted the chairman of the election commission to call for a criminal investigation. "They want to carry out elections in a controllable regimen," Mr. Glazyev, a leader of the Motherland bloc who is running without his party's support, said in a telephone interview on Wednesday. "They want to manipulate all the candidates and turn the elections into a political spectacle."

Secretary of State Colin L. Powell used a visit to Moscow this week to rebuke Mr. Putin for what he said were troubling developments in Russian democracy, including the fairness of elections and candidates' access to state television. "Key aspects of civil society — free media and political party development, for example — have not yet sustained an independent presence," Mr. Powell wrote in an article in Izvestia.

But the presidential election on March 14 is shaping up as a repeat of last month's parliamentary election, which the party loyal to Mr. Putin, United Russia, swept after a campaign criticized by international observers as falling short of democratic standards.

With a deadline for submitting at least 2 million signatures having passed Wednesday night, Mr. Putin now faces a diminished field of six challengers, two of whom openly support his re-election on March 14.

"I am not an opponent to Mr. Putin so I don't want to interfere with his campaign," Vladimir A. Bryntsalov, a pharmaceuticals and vodka magnate, said in an interview on Wednesday after abruptly ending a campaign that never really began.

The election commission now has 10 days to verify the signatures of the remaining candidates. Mr. Putin's critics, including Ms. Khakamada and, increasingly, Mr. Glazyev, fear that they could still be thrown off the ballot. Viktor V. Geraschenko, a former central bank chairman who also represented Motherland, has already been declared ineligible on the technicality that Motherland is a political bloc and not an officially registered party. Mr. Geraschenko has appealed that decision to the Russian Supreme Court.

Mr. Putin's challengers complain that they are facing bureaucratic obstacles and the vast administrative resources of local governments controlled by the president's allies. They are also struggling — in vain, they say — to get their views heard on state newscasts dominated by coverage of Mr. Putin.

In programs on Tuesday night, he appeared in St. Petersburg, solemnly commemorating the 60th anniversary of the end of the World War II siege on the city then known as Leningrad. The news on Wednesday featured his order to prevent "an uncontrolled rise in bread prices."

Mr. Putin, for his part, has made no overt signs of campaigning. Given his sky-high popularity, most here expect he never will. The latest poll, published Wednesday, showed Mr. Glazyev coming in second place with 4 percent of the vote. Mr. Putin was favored by 79 percent.

"Look at what is happening," Ivan P. Rybkin, another of Mr. Putin's remaining challengers, said in an interview on Wednesday. "The law guarantees equal rights for candidates, equal rights to present themselves. For now, there is only one candidate."

Even in the comparatively free print media, the election is considered a foregone conclusion. In some cases, Mr. Putin's challengers are treated with contempt.

In addition to Mr. Rybkin, Mr. Glazyev and Ms. Khakamada, the other candidates are Nikolai M. Kharitonov, a former collective farmer and leader of the Agrarian Party who was endorsed by the Communist Party; Sergei M. Mironov, the chairman of the upper house of Parliament, who supports Mr. Putin's reelection; and Oleg A. Malyshkin, the former bodyguard of Mr. Zhirinovsky, who was elected to Parliament in December representing the nationalist Liberal Democratic Party.

Mr. Rybkin, Ms. Khakamada, Mr. Glazyev and Mr. Kharitonov have presented their candidacies as quixotic efforts to debate Russia's myriad problems and present alternatives to Mr. Putin's political dominance.

Sophia Kishkovsky contributed reporting for this article.