Vladimir Putin the Russian opposition and by international observers from the Organization for Security and Co-operation in Europe for procedural irregularities. Anti-Putin protests took place during and directly after the presidential campaign. The most notorious protest was the Pussy Riot performance on 21 February, and subsequent trial. An estimated 8,000–20,000 protesters gathered in Moscow on 6 May, when eighty people were injured in confrontations with police, and 450 were arrested, with another 120 arrests taking place the following day. A counter-protest of Putin supporters occurred which culminated in a gathering of an estimated 130,000 supporters at the Luzhniki Stadium, Russia's largest stadium.
Vladimir Putin period of demographic collapse that began in the 1990s. At the United Russia Congress in Moscow on 24 September 2011, Medvedev officially proposed that Putin stand for the Presidency in 2012, an offer Putin accepted. Given United Russia's near-total dominance of Russian politics, many observers believed that Putin was assured of a third term. The move was expected to see Medvedev stand on the United Russia ticket in the parliamentary elections in December, with a goal of becoming Prime Minister at the end of his presidential term. After the parliamentary elections on 4 December 2011, tens of thousands of Russians