He became popular with the documents about lawlessness. The CHP nominated him as candidate for Mayor of Istanbul in 2009 local elections, in which he gained 36.8% of all votes. Despite this result he could not be first. However this result was a big success for social democrats because they had not ruled Istanbul for many years and this city had become the power centre of AK Parti for long years. This popularity provided him with a great advantage. Upon Deniz Baykal's resignation in 2010, Kemal Kılıçdaroğlu became the leader with a record voting rate.