Sung Woan-jong, a construction company owner who died in an apparent suicide early this month, is posthumously rocking the nation with a list of powerful figures, who he alleged had received large sums of money from him. The snowballing graft scandal is pushing President Park Geun-hye into a corner, as most people on the list are close to her.

The prosecution’s investigation, prompted by Sung’s allegations, however, is expanding beyond the list to look into his dubious deals with a wider range of politicians and high-ranking officials. What draws increasing attention is that Sung was granted special amnesty twice during President Roh Moo-hyun’s five-year tenure, which ended in February 2008.

The liberal president pardoned Sung in 2005 and 2007 for his earlier convictions of offering illegal political funds to a now-defunct political party and unlawfully causing losses to his company. As Justice Ministry officials concede, it was rare for a convict to have been pardoned twice by the same president.

Aides to Roh were said to have included Sung’s name in the 2007 amnesty list despite repeated objections from the ministry. They now say they did so at the request of figures close to Lee Myung-bak, who was elected to succeed Roh in the presidential election that year. In reality, Sung might have lobbied both sides.

Park seems to be highlighting Sung’s amnesty to counter a political offensive from the main opposition New Politics Alliance for Democracy led by a former confidant to Roh. In a statement issued Tuesday to reaffirm her will to clarify all suspicions surrounding Sung’s allegations, Park also stressed the need to dig up the truth behind his pardoning, which she said was difficult for the public to understand and undermined the rule of law.

The dispute over the dubious pardoning of the deceased businessman should not be allowed to dilute attention to the investigation into the list and recorded testimony left behind by Sung before his death. But it can certainly serve to reflect on and improve the practice of abusing the presidential authority to grant special pardons.

It has become routine for an incumbent president to exercise this privilege on nearly every occasion available. In many cases, those freed included politicians, business tycoons and senior public officeholders close to the president.

Roh conducted special amnesties eight times during his term in office. The number was similar to those for his successor Lee and two predecessors Kim Dae-jung and Kim Young-sam.

It should now be recalled that the presidential right to grant special pardons is justified only when it is exercised to reflect on critical changes in laws and social conditions.

President Park deserves some credit for having been more cautious than her predecessors in exercising the right. Since taking office in February 2013, she has conducted one amnesty, from which politicians, high-ranking officials and corporate executives were excluded.

During the remainder of her presidency, Park should abide by the strict standards for granting amnesty. It is also necessary to stipulate specific requirements for being pardoned and make it obligatory to give a detailed explanation on each individual case.