He has been the leader of the Victorian Division of the Liberal Party of Australia since May 2006 and Premier of Victoria since 2 December 2010 after the Liberal\/Nationals Coalition defeated the Brumby-led Australian Labor Party government with 45 seats to 43 in the Legislative Assembly . He has been the leader of the Victorian Division of the Liberal Party of Australia since May 2006 and Premier of Victoria since 2 December 2010 after the Liberal\/Nationals Coalition defeated the Brumby-led Labor Party government with 45 seats to 43 in the Legislative Assembly .