Combination photo taken from file pictures show ruling right-wing conservative Saenuri Party's interim leader Park Geun-hye speaking in Seoul April 12, 2012 (L) and Moon Jae-in, lawmaker of the main opposition Democratic United Party and former human rights lawyer, speaking in Goyang September 16, 2012. South Korea's December presidential election looks set to turn into a referendum on two of the country's most polarizing leaders as Park, the daughter of military dictator Park Chung-hee, faces off against Moon, a former aide to ex-President Roh Moo-hyun. REUTERS/Kim Hong-Ji (L)/Lee Jae-Won (R)/Files (SOUTH KOREA - Tags: POLITICS ELECTIONS)