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 engaged in protests against alleged electoral fraud, the largest protests in Putin's time. Protesters criticized Putin and United Russia and demanded annulment of the election results. Those protests sparked the fear of a colour revolution in society. Putin allegedly organized a number of paramilitary groups loyal to himself and to the United Russia party in the period between 2005 and 2012. 2012–2018: Third presidential term On 24 September 2011, while speaking at the United Russia party congress, Medvedev announced that he would recommend the party nominate Putin as its presidential candidate. He also revealed that the two men had long ago cut a deal to allow Putin to run for president in 2012. This switch was termed by many in the media as "Rokirovka", the Russian term for the chess move "castling". On 4 March 2012, Putin won the 2012 Russian presidential election in the first round, with 63.6% of the vote, despite widespread accusations of vote-rigging. Opposition groups accused Putin and the United Russia party of fraud. While efforts to make the elections transparent were publicized, including the usage of webcams in polling stations, the vote was criticized by 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. Some of the attendees stated that they had been paid to come, were forced to come by their employers, or were misled into believing that they were going to attend