South Koreans cast ballots today in a tight parliamentary vote that centred on domestic issues but has implications for Seoul's relationship with the North.
Exit polls suggested President Lee Myung-bak's conservative ruling party and his liberal rivals were neck and neck in the race for 300 parliamentary seats.
A ruling party defeat would pose a blow to Lee, who has taken a hard line on North Korea since taking office in 2008.
"The liberals would demand Lee's government pursue an appeasement policy on North Korea," said Chung Jin-young, a political scientist at South Korea's Kyung Hee University. "So a liberal win would be favourable for North Korea."
Ties between the two Koreas plummeted during Lee's tenure, with two attacks Seoul blames on Pyongyang killing 50 South Koreans in 2010. North Korea also conducted a long-range rocket launch and tested a nuclear device in 2009.
After North Korean leader Kim Jong Il died in December and his son Kim Jong Un took over, Pyongyang stepped up criticism of Lee, accusing his government of failing to pay proper respect to Kim Jong Il.
South Korea, the US and others have urged the North to cancel a rocket launch it plans as soon as tomorrow, calling it a cover to test long-range missile technology rather than the peaceful satellite launch Pyongyang claims. Lee's government has said it will shoot down any rocket parts that threaten to fall onto the South's territory.
Despite Pyongyang's rocket preparations, the launch wasn't a major issue in today's elections, which were largely seen as a way to gauge public sentiment ahead of December's presidential polls. Voters have said they care more about economic and other domestic issues.
Kim Doh-jong, a professor at Seoul's Myongji University, said that even if there's a big liberal win, there's little chance Lee will back down on North Korea.
"He cannot change his North Korea policy at a time when the US, Japan and other countries maintain a firm stance on North Korea," Kim said.
Lee's single five-year term ends early next year.
Key potential contenders vying to succeed Lee are Park Geun-hye, a top ruling party official and the eldest daughter of late President Park Chung-hee; Moon Jae-in, a liberal opposition leader who served as former President Roh Moo-hyun's chief of staff; and Ahn Cheol-soo, a university professor and founder of one of South Korea's most successful software companies.