With President Park Geun-hye embarking on a 12-day South American tour, Prime Minister Lee Wan-koo will be in charge of state affairs as the acting president during Park’s absence. Normally, this would not be newsworthy, except we now have an unprecedented situation where the sitting prime minister is facing an investigation for allegations of accepting illicit money from a businessman.

The late Sung Woan-jong, former chairman of Keangnam Enterprises, claimed in a telephone interview conducted before his suicide and released Tuesday, that he had given 30 million won to Lee in April 2013 when he was running for parliament. Lee’s name also appears on a memo found on Sung’s person at the time of his death that contains a list of eight names and figures indicating sums of money next to six of the names. Lee’s name did not have a figure next to it.

Lee vehemently denied the allegation, claiming that he did not receive any money from Sung. He went so far as to say that he would give up his life if he is found to have received Sung’s money.

However, calls are mounting, even among the Saenuri Party members, for Lee’s resignation. On Tuesday, the party held a special meeting to discuss the matter, which ended inconclusively. While the opposition called for Lee to step down, or at least have his authority suspended while he is being investigated, the latter is not an option, as it is without legal grounds.

Lee said the office of the prime minister is of such weight that it is not something that should be given up because of allegations. He showed his resolved to keep his position, insisting that he will be investigated as a prime minister. He also asked to be the first to be investigated.

However, Lee does more to tarnish the dignity of the office of the prime minister by insisting on maintaining the position while being investigated. There is also the practical question of whether a thorough, no-holds-barred investigation would be possible, with the prime minister also a subject of the probe.

When the general distrust in the prosecutors and the extraordinary nature of the unfolding incident necessitate considering a special prosecutor investigation, Lee’s insistence on keeping his position does a great disservice to the country. As the prime minister, Lee should think first and foremost about the consequences his actions will have for the country.