Vladimir Putin's governing party is likely to see its huge parliamentary majority cut on Sunday in a sign of growing weariness with his 12-year rule and the prospect of over a decade more in power.
Sunday's parliamentary election is the first electoral test since the powerful prime minister upset some Russians by announcing plans to swap jobs with President Dmitry Medvedev next year, possibly extending his rule until 2024.
Posters for Putin's United Russia dominate Moscow streets exhorting Vote for Russia, Vote for Yourself, with markedly fewer presenting liberal Grigory Yavlinsky's Yabloko party or the jabbing finger of nationalist Vladimir Zhirinovsky.
Opinion polls show the former KGB spy, whose crushing of a rebellion in the Chechnya region helped build the image of a strong leader, remains Russia's most popular politician.
But they also show his popularity, further enhanced over the years by stunts such as bare-chested horse riding, hit its lowest point in a decade last month before rising again. His United Russia party, though winning the poll, seemed likely to lose the two-thirds majority that eases constitutional changes.
In what one opposition blogger called the end of an era, the 59-year-old leader was even booed when he spoke at a martial arts fight last month.
He is not losing power but he realises he is losing the people, said a source close to Putin, who is more powerful than Medvedev despite ushering him into the Kremlin in 2008 to skirt a constitutional ban on a third successive term as president.
Putin is all but certain to win a presidential election in March but will want to avoid a big election setback now that might threaten the support of the business and political elite who have helped prop him up for more than a decade.
Some commentators say he may be losing touch with the millions of Russians who suffer low living standards despite Russia's vast energy resources, fear political and economic stagnation and have little say in how the country is run.
The Russian people saw benefits when Putin took power. But now they see Russia's isolation growing, they see Russia is not getting up off its knees, they feel they are being cheated, said political analyst Dmitry Oreshkin.
United Russia will win this election but in the long or medium term disappointment will keep growing and the authorities' legitimacy will fall unless changes are made.
United Russia, which has dominated the Duma since 2003, is expected to retain a clear majority in the chamber though the two-thirds that allow it to pass constitutional changes without opposition support may prove out of reach.
Many voters say they expect the party's result to be boosted by vote rigging and favourable coverage by traditional media. A liberal party led by former Prime Minister Mikhail Kasyanov and two allies is barred from even taking part.
The latest survey by Russia's biggest independent pollster said United Russia would win 252-253 places in the 450-seat Duma, down from the 315 places it has now.
The biggest gainers would be the Communist Party, which is likely to remain the second biggest force 20 years after the fall of the Soviet Union, although critics say it and other parties in parliament form only a token opposition.
The main centre of power in the country of 142 million is the executive, so losing ground in the Duma will do little more in practice than at times limit the ability of the government and Kremlin to push through major legal changes.
But a less than stellar showing by United Russia would reinforce the impression that Russians are starting to tire of Putin and his party, which ex-Soviet leader Mikhail Gorbachev has called a bad copy of the Soviet Communist Party.
This election is important as a prelude to the election in March and as a gauge of public opinion, said Dmitry Trenin, head of the Moscow Carnegie Centre think tank.
A disappointing result for United Russia could also undermine Medvedev because he tops the list of the party's candidates. He could be blamed for any setback, raising questions about his ability to become or stay long as premier.
If there's a bad result for United Russia, it will be used against Medvedev, said political analyst Gleb Pavlovsky.
FEAR OF FRAUD
Supporters still praise Putin for restoring order after the chaos of President Boris Yeltsin's rule in the 1990s following the collapse of the Soviet Union in 1991. There was also an oil-fuelled economic boom during his presidency until 2008.
I like the current authorities. I'm doing well. I like Putin too. He's got my first name, he's a normal guy and he doesn't hinder my work, said the 37-year-old head of a dental clinic in Moscow who gave his name only as Vladimir.
Russia has a growing middle class and a small number of people have become extremely rich, but many others have not felt the benefits of the boom.
Capital flight this year is put at about $80 billion -- a sign of low confidence -- and, although down from its peaks, annual inflation is still running at around 7 percent.
Real disposable incomes have risen by 2.7 times since Putin came to power in 2000, but have fallen this year for the first time since the 2008 financial crisis, helping to sour the mood. The average monthly wage is still only about $760.
Many Russians show little interest in elections and politics because they fear fraud in a country where democracy still has a relatively fragile hold following seven decades of communism.
It would be naive to think my vote would count. Everything has been determined, said Rimma, a 32-year-old accountant in Tula, south of Moscow, who declined to give her last name.
Medvedev has said United Russia will win the election fairly and the Organization for Security and Co-operation in Europe's election watchdog branch will monitor voting.
Opposition parties have been able to take part in televised election debates and promote themselves in TV campaign clips, but complain that Putin and Medvedev refused to join the debates and benefit from fawning coverage by traditional media.
Polling stations are open from 8.00 a.m. to 8.00 p.m. local time on Sunday, with voting starting in Russia's Far East at 8 p.m. British time on Saturday and ending in Kaliningrad, its westernmost territory, at 1 a.m. British time on Sunday. Seven parties are taking part.
(Additional reporting by Lidia Kelly, Steve Gutterman and Lyudmila Danilova)