The race to succeed Boris Yeltsin officially commenced today with the front-runner, Acting President Vladimir Putin, collecting fresh endorsements and dominating the airwaves in what many politicians and commentators described as more like a prelude to a coronation than a competition.

The Federation Council, the upper house of parliament, voted 145 to 1 to hold the vote on March 26, allowing formal campaign activities to begin Thursday, including collection of the half-million signatures each candidate needs to get on the ballot. Most candidates simply hire companies to gather the signatures.

As politicians returned after the extended New Year's holiday, Putin continued to demonstrate his preeminent position in the shortened campaign triggered by Yeltsin's surprise resignation Dec. 31. A group of prominent governors, whose campaign bloc was known as All-Russia and who were earlier allied with Moscow Mayor Yuri Luzhkov, announced they would back Putin's presidential bid.

Putin, who has been given adoring news coverage by state television and a channel directed by a business tycoon close to the Kremlin, was hailed repeatedly today as the only candidate likely to win the election.

At the same time, some newspaper commentators have begun to question whether Putin's head start is healthy, but political leaders were loath to criticize the former KGB agent whom Yeltsin anointed as his heir.

Grigory Yavlinsky, the leader of the centrist Yabloko faction who has announced plans to run, acknowledged Putin's advantage. "To say that one can defeat Putin today is just not serious," he said in a radio interview. "If everything stays the way it is now, Putin will win the presidential elections."

Yavlinsky said he would run anyway "in the interests of change for the better in this country, for a breakthrough, for the sake of preserving openness [and] democracy."

Kirsan Ilyumzhinov, president of the Kalmykia region of southern Russia and an authoritarian figure there, said, "I see no serious contenders" to Putin. "Someone may register so that the elections won't be canceled. . . . But in fact there are no real opponents to Vladimir Putin now."

Putin's backing helped a pro-Kremlin party make a strong showing in last month's parliamentary election--a group some skeptics dubbed a "virtual party" because it had no program other than support for Putin. Today, Ludmila Telen, a longtime Kremlin observer and deputy editor of the English-language Moscow News, expressed reservations about the speed with which Putin--unknown to the Russian electorate until Yeltsin named him prime minister just five months ago--is being crowned Yeltsin's heir.

"Having appointed Putin acting president, Yeltsin in essence appointed us acting voters," she wrote. "The form has turned out to be impeccably democratic. That can't be said about the content."

Tatyana Malkina, another political commentator who covered Yeltsin's 1996 election campaign, said: "Boris Yeltsin has given us as a present to his successor, Vladimir Putin. Perhaps not everyone can detect the fundamental anti-democratic character [in this]. But the general cynicism of this . . . is obvious . . . "

The short election campaign has given Putin's potential rivals pause. Aman Tuleev, governor of the Kemerovo region in Russia's coal basin and a former top Communist Party official, said: "If we are to be frank, the election is being arranged to suit Putin. I think anyone with a head on their shoulders can see that."

For many candidates, it may be difficult, if not impossible, to mount a challenge in the short time until election day. Putin controls two of Russia's three major television channels, the major source of news for most Russians.

The Kremlin and its allies among a politically influential group of business tycoons engineered a smear campaign in the parliamentary races against Luzhkov and former prime minister Yevgeny Primakov. Today, Putin, without mentioning those tactics, implored political leaders to make sure "this campaign takes place absolutely within the existing laws, is extremely clean and devoid of all mudslinging and aimed at only one thing--the creation of a level playing field for all participants in the process."

But the playing field is not level, and Putin's rivals know it. Primakov, who announced Dec. 18 that he will run, has remained silent since Yeltsin's resignation. Besides Yavlinsky, the Communist Party and its allies are also expected to field a candidate, but polls show that Putin remains the odds-on favorite--a popularity stemming largely from his vigorous prosecution of the war against separatist rebels in Chechnya.

Putin, meanwhile, is dominating post-Yeltsin media attention. On Tuesday night, the acting president was featured in a lengthy interview on state television in which he compared Yeltsin's retirement to that of his own father. Expressing sympathy for Yeltsin's plight, the hard-edged Putin, who was recently featured flying jet planes and practicing judo, offered folksy sayings, such as, "We must treat our parents as we want to be treated by our own children."

The official Russian Tass news agency also reported today on some aspects of a skiing vacation taken by Putin's wife Ludmila and their two daughters. Previously, his family has been carefully shielded from public view.

CAPTION: The ascendancy of Vladimir Putin has commentators questioning the vitality of Russian democracy.