President Vladimir Putin’s ruling party decisively swept regional elections, according to results tabulated Monday, paradoxically confronting his top-down authoritarian system with a serious challenge.

Since December’s parliamentary vote, when large numbers of demonstrators unexpectedly began protesting rigged elections, Putin and his allies have been trying to regain what had been an undisputed grip on power. Sunday’s election would appear to confirm they had done so.

The United Russia party won all five governorships at stake and dominated all six regional legislatures up for election, along with a host of municipal councils and mayoralties. Yet political observers called it an illusory victory because serious challengers were kept off the ballot, either through the inventive use of election laws or by secret deals. That meant Putin opponents found no outlet at the polls for their anger.

“If the party of power continues playing games with imitation elections,” said Boris Makarenko, an independent political analyst, “the opposition will have to challenge them on the streets instead of at the polls.”

Makarenko, chairman of the board of the Center for Political Technologies, said it was in United Russia’s interest to work for political pluralism, to determine the country’s direction through elections. But he was unsure, he said, whether authorities understood that.

Putin took the results as a sign of victory. “I believe that they represent one more step confirming the intention of voters to support the current institutions of government and the development of Russian statehood,” he said Monday.

Georgy Bovt, a political analyst and columnist, said the election results suggested that no opposition has been able to develop on the regional level. He noted that the strength of the opposition has not been tested in Moscow, where elections were not held.

“Probably it’s a movement limited to Moscow,” he said. “In provincial Russia, it’s nonexistent. And they are not up to the challenge of opposing United Russia.”

‘A propaganda machine’

A look at the city of Izhevsk, 600 miles east of Moscow, offers a sense of the opposition’s despair. Andrei Konoval, a journalist and a leader of the Patriots of Russia party, was too afraid to speak to an American reporter who visited Izhevsk last month before the election. He was convinced that talking to the reporter could be sufficient pretext for the authorities to take him off the ballot — after all, Putin had been sending an anti-American message from Moscow. Monday, with the election over and his efforts a failure, he spoke at length by telephone.

Konoval said the entire regional administration bent its efforts toward preventing any member of the opposition from being elected to the local legislature. “Every public agency and private company was turned into a propaganda machine for the party of power,” he said. The head of the region told everyone, from school principals to factory owners, that they and their employees were expected to vote for United Russia, he said.

“Then, there were many absentee ballots issued, so your boss could watch you vote and make sure you voted right,” he said. “In rural areas, they used this approach: If you vote wrong, you will have problems. Not only you, but your town, your school, your organization will suffer, because you’ll be cut off from government money.”

During a previous election, Konoval was accused of continuing to work at his newspaper job during the campaign — interpreted as an abuse of power — and he was struck from the ballot just days before the election. The effect was so chilling, he said, that he and his allies were afraid to campaign vigorously this year.

“So we had to be quiet and careful,” he said. “Any wrong movement and we would be out. Many people in Izhevsk did not even notice there was an election.”

Konoval’s newspaper, the only independent one in the city, refrained from writing articles that might be considered critical of the authorities — another possible abuse of power.

Turnout ranged from 30 percent in Izhevsk to 40 percent in rural areas of the region, where pressure on voters was more intense. “You could say most voters boycotted the election, because they didn’t see any use in casting their ballot,” Konoval said.

United Russia will again dominate the regional legislature with about 65 percent or 70 percent of the seats, Konoval said, continuing to make it difficult for political challengers to emerge.

Hurdles for opposition

For the past decade, Putin has limited competition so successfully that few opposition leaders have any significant political experience. The recent protests have forced some change — the election of governors, for example, which Putin was able to eliminate as of 2005, has been phased back in, with five elections this year and more planned a year from now. But all Putin-backed governors won easily Sunday, with anywhere from 64 percent to 77 percent of the vote, as did the United Russia incumbent candidate for mayor in the Moscow suburb of Khimki.

There, a dynamic opposition leader, Yevgenia Chirikova, won 17 percent of the vote, running against the United Russia incumbent, Oleg Shakhov, who got 48 percent. Several other candidates — including some allegedly put up by the authorities to run — helped split the opposition vote.

Vladimir Churov, chairman of the Central Election Commission, said there were relatively few reports of violations and none that would have affected the outcome. “Some of them were purely technical in nature,” he said.

But election monitors from the independent Golos agency said they registered about a thousand complaints of election violations nationwide. Lilia Shibanova, director of Golos, said that the official attitude has grown even more negative toward monitors and their complaints and that elections have not become more fair.

“Unfortunately, the situation is getting worse,” she said.

People see the state as corrupt and ineffective, said Bovt, the political analyst, but they tolerate it, unwilling to do anything about it. Eventually, he said, external pressure or rivalry within the elite may disrupt the status quo.

“Change may come,” he said, “but it won’t be from the ballot.”