FRESH from hosting a grand nuclear-security summit attended by the presidents of America and China, South Korea’s president, Lee Myung-bak, has been hurled summarily into tawdry politics at home. The ruling Saenuri Party, until recently known as the Grand National Party, has had a year of scandals. Now Mr Lee faces what his critics are calling a Korean Watergate.

Journalists at Korean Broadcasting System (KBS), who are on strike along with colleagues at two other stations, claim that they have over 2,600 files that point to illegal surveillance carried out between 2008 and 2010 by a government “ethics team”. Targets are understood to have included journalists, opposition politicians, critics of the president and even a foundation set up by the chairman of Samsung, the country’s mightiest conglomerate.

The reporters walked out of KBS last month over what they see as government interference in news coverage. Their new claims, courtesy of a whistleblower’s memory stick, seem excruciatingly timed. Elections for the National Assembly will be held on April 11th. Yet whereas the furore can only harm Mr Lee’s reputation, it may not stop his party from winning the parliamentary election.

For a start, the government claims that 80% of the files relate to investigations ordered by the previous administration of President Roh Moo-hyun (who committed suicide in 2009). If true, this could damage the main opposition, the centre-left Democratic United Party (DUP). Its leader is Han Myung-sook, who served as prime minister under Roh in 2006-07. The DUP is the descendant of Roh’s Uri Party.

For her part, Ms Han argues that the illegal surveillance means “the spirit” of South Korea’s post-war strongman, Park Chung-hee, still roams the land. This is an obvious dig at the dictator’s daughter, Park Geun-hye, who now leads the Saenuri Party and who is the front-runner to replace Mr Lee in the presidential election in December.

Ms Park has in fact engineered a rebound in Saenuri’s popularity, by distancing herself from Mr Lee, who a majority of the public believes is doing a bad job. Cleverly, she has used the scandal to criticise both the previous and the current administration as examples of “old, wrong politics”. And she suggests she too may have been a target of the snooping.

As for the parliamentary elections, a poll conducted on March 31st by the Korea Society Opinion Institute gives Saenuri support of 38.8%, with the DUP a little over five points behind, compared with a deficit of nine points before the surveillance scandal broke. Because voters are worried about job security and access to welfare, concerns the DUP plays on, it is surprising the party trails at all. Yet it has problems of its own. It made an about-turn in its support for a controversial free-trade deal with America, which it had proposed when in power, as well as for the construction of an unpopular new naval base. The cynicism that motivated the U-turns turned voters off in droves.