Prime Minister Vladimir V. Putin on Tuesday stepped down as chairman of United Russia, a post he has held since 2008, handing the reins of the parliamentary majority to his protégé, President Dmitri A. Medvedev.
The move binds together two political forces that were much weakened by the tumult of the last six months.
United Russia was already losing popularity when it engaged in heavy-handed vote-rigging at last December’s parliamentary elections, sparking large street protests in Moscow and other large cities.
Mr. Medvedev’s political capital, meanwhile, was seriously damaged by the September announcement that he would step down after one presidential term to make way for Mr. Putin to return for a third term. He will serve as prime minister after Putin is inaugurated.
The combination is also awkward for other reasons: As president, Mr. Medvedev styled himself as an advocate of political reforms within Putin’s team, and harshly chided United Russia for what he called “backwardness,” warning that party members “need to learn to win in open contests.”
Party members on Tuesday dutifully promised to support Mr. Medvedev’s chairmanship, but some made it clear that they still view Mr. Putin, the more popular and powerful of the two, as the party’s true leader.
Mr. Putin “has been and remains the moral leader and the creator of our party,” said Andrei Isayev, a top official, in an interview. Mr. Medvedev, he said, “will run the party on a day-to-day basis. Moreover, the party will be a tool — a force that will guide policy and strategy and the government will implement it.”
One party member, Aleksei Chadayev, wrote via Twitter that he plans to throw out his party card, explaining that “for some reason I don’t want to be the new gadget for the heir” to Mr. Putin.
Mr. Putin said he was stepping down because he sees the role of president as one of “a consolidating figure for all political forces,” and not affiliated with any one party.
But analysts, especially those aligned with the opposition, said Mr. Putin is distancing himself from United Russia because its image has been irreparably damaged, among other things by a derisive nickname that spread via social networks last year, “the party of swindlers and thieves.” Stanislav A. Belkovsky told Dozhd, an Internet-based news channel, that Mr. Medvedev and United Russia are both heading for “a slow clinical death.”
Mr. Medvedev, whose four-year term will end in two weeks, gave his final address as president on Tuesday morning, recalling words that he spoke as a candidate — “freedom is better than non-freedom.” That 2008 speech inspired some to hope for major reforms during his presidency.
“These words were later repeated by many different people, sometimes with hope, sometimes with reproach, as a demand or a reminder of a promise,” Mr. Medvedev said. “I followed this ideal as closely as I could.”
In the address, Mr. Medvedev took credit for rolling back two laws that helped consolidate the Kremlin’s grip over Russian politics: an extraordinarily high threshold for political parties to participate in elections and the elimination of directly-elected governors. That level of central control, he said, made sense a decade ago but gradually became a drag on Russia’s development.
“The system stabilized, and as always happens — in accordance with the laws of philosophy — after its stabilization one started to notice signs of stagnation,” Mr. Medvedev said. “There arose the question of what to do — to leave everything as it is? To rely on ‘manual operation,’ to make that the permanent norm of political life — or to return to a more efficient development, on the basis of direct participation of citizens in politics? I think the conclusion is obvious.”
Mr. Medvedev promised that, as prime minister, he would reduce state control over the economy and continue to fight corruption.