SEOUL - South Korea's Supreme Court on Thursday upheld a one-year jail term for a former opposition lawmaker charged with spreading false rumors about President Lee Myung-bak's involvement in a fraud.

The sentence for Chung Bong-ju, affiliated with the liberal main opposition United Democratic Party, renders him ineligible to run for office for the next 10 years.

Before the 2007 presidential election, Chung led opposition efforts to link Lee, then a strong presidential contender, to a financial scam also involving a Korean-American businessman now in jail.

Lee was cleared of all charges before taking office in early 2008, but his critics have nonetheless raised suspicions he was also behind a stock manipulation scheme.

Chung recently rose to stardom through his appearances on a widely popular podcast show called "Naneun Ggomsuda", or "I'm a Wesel".

Chung and his three other co-hosts have raised a series of allegations of irregularities involving Lee, rekindling public interest in the financial scheme.

The United Democratic Party, meanwhile, said the court ruling Thursday "does not make sense," vowing to continue their "fight against lies and hypocrisy."