Former world chess champion Garry Kasparov has been selected to be the candidate of an opposition movement in next year's Russian presidential poll.
Polls suggest Mr Kasparov has little chance of winning the election
He won overwhelming backing at a congress of the small Other Russia coalition, fending off five rivals.
After his selection, he vowed to fight for a "democratic and just Russia".
Opinion polls suggest Mr Kasparov has little chance of victory against whomever receives the backing of the outgoing President, Vladimir Putin.
Mr Putin is barred by Russia's constitution from standing for a third consecutive term in March 2008.
In the primary election, Mr Kasparov received 379 out of the 498 votes cast, beating other nominees including former Prime Minister Mikhail Kasyanov and the former head of the Russian Central Bank, Viktor Gerashchenko.
"I will do everything possible for the ideas of The Other Russia to win," Mr Kasparov told the meeting.
"This will work only if we stay united. I know that the road will be difficult."
Mr Kasparov, who founded The Other Russia, has become one of President Putin's most outspoken critics since he retired from chess and turned to politics in 2005.
His coalition includes both mainstream politicians and fringe groups from both ends of the political spectrum. The movement's numbers are small, with supporters at recent rallies generally outnumbered by police.
"The goal of the Other Russia is not winning elections, but to have an election," he told the Associated Press.
"We're trying to force the regime to accept our rights to participate in free and fair elections, to [canvas] the Russian population and Russian public to support our ideas."
The coalition also chose Mr Kasparov to be one of three candidates to head its list in the parliamentary election in December.
However, its participation is unlikely as none of the parties in the coalition have qualified.