By Maria Tsvetkova
MOSCOW (Reuters) - Supporters applauded and chanted "We will win" in a Moscow courthouse on Thursday as 12 Russians went before a judge charged with mass disorder during a protest against Vladimir Putin.
The protestors could face long prison terms if convicted over clashes with police in May last year on the eve of Putin's return to the presidency.
Putin critics liken the case to Soviet-era show trials and say the result will be decided in the Kremlin. They say the prosecutions are part of a new clampdown on dissent by Putin, now in his third term as president.
The Russian leader has signed laws activists say restrict freedoms, civic groups are under pressure from the state over their funding and prominent opposition leader Alexei Navalny faces 10 years in jail if convicted of theft - a charge he says is Putin's revenge for his activism.
Most of the 12 defendants, many of whom are in their 20s, could be jailed for eight years if convicted. Most have been in custody or under house arrest since their detention.
"This is a Stalin-style trial," said Georgy Satarov, a former aide to the late President Boris Yeltsin and now head of INDEM, a think-tank. "This is revenge ... It's an attempt to use fear to stop the growth of the protest movement."
The rally on the eve of Putin's inauguration followed a wave of peaceful protests that were fuelled by claims of fraud in a parliamentary election and dismay at Putin's decision to return to the Kremlin after a stint as prime minister.
Putin denies he is seeking to stifle dissent, saying people have the right to protest peacefully but condemning violence against police. In April, he denied he has returned "elements of Stalinism" but said Russia needs "order and discipline."
The protests were the biggest of Putin's 13 years in power, but they have since dwindled, though a new protest march is planned for June 12 along a route ending at Bolotnaya Square.
Artist Andrei Barabanov, one of a total of nearly 30 people facing trial or prosecution over the May 6, 2012 protest, was dragged away so roughly by police that an ambulance had to be called for him.
Like most of the defendants he has no previous criminal record and says all he did was defend himself against police.
Police say protesters struck them with plastic flagpoles and metal crowd barriers and that some hurled chunks of asphalt. They said more than 40 officers were hurt.
Satarov co-authored a report by public figures and human rights advocates, based on video footage and witness interviews, that accused police of using excessive force and squeezing protesters into a confined space, causing panic.
"What I saw was mass disorder on the part of the police," said Barabanov's girlfriend Yekaterina, who declined to give her last name. She called the case a "huge pile of lies".
Bestselling crime novelist Boris Akunin, who has spoken at several protests, defended Barabanov in a video statement in April. "He is not a political activist, he is like most of us - people who went to the demonstration because we were fed up."
"It is absolutely clear that everything has been decided ahead of time and as a result Andrei Barabanov will be jailed," he said.
(Additional reporting and writing by Alissa de Carbonnel; Editing by Steve Gutterman)