President Lee Myung-bak told his senior secretaries that his was a “morally perfect administration” and that, as such, it “should not permit even the tiniest blemish.” He made the remarks in reference to corruption allegations against some of his aides on Sept. 30 last year.

It was not clear whether he actually believed in his administration’s moral supremacy or intended his remarks to be mere political rhetoric. But a stern-faced senior presidential secretary, emerging from a meeting presided over by the president, quoted him verbatim, as if his words were written in stone.

But the corruption scandals involving those who helped his election to the presidency five years ago, culminating in the recent arrest of his older brother, are dragging the Lee administration into moral bankruptcy. His authority as the head of state is crumbling, with one erstwhile staunch supporter after another being prosecuted as his administration enters the homestretch.

This is truly deplorable, and all the more so, given that the next administration will probably be riddled with corruption, too, if no institutional changes are made to help discourage it. Notable among the proposed changes are restrictions to the president’s constitutional privilege to grant amnesty and the creation of a new agency for criminal justice against members of the president’s family and top public officeholders.

Criminal justice is often thwarted by the unrestrained use of presidential amnesty. President Lee and his predecessors included political big shots serving prison terms on conviction of bribery among those granted amnesty on Independence Movement Day on March 1 and National Liberation Day on Aug. 15.

Few would believe that justice is served when a presidential decree releases from prison a member of the presidential family or a former high-ranking government official who took hundreds of millions of won in bribes. They deserve harsher treatment than a hard-pressed person put in prison for stealing food, because they have abused their political influence or posts for lining their pockets.

A news report is encouraging that Rep. Park Geun-hye of the ruling Saenuri Party, who has recently declared her bid for the presidency, is considering including restrictions on presidential amnesty among her election promises. Other presidential hopefuls will probably jump on the bandwagon if she decides to commit herself to reducing this presidential privilege.

The main opposition Democratic United Party is more enthusiastic than the Saenuri Party when it comes to the proposal to establish a new law-enforcement agency empowered to launch investigations into cases involving members of the first family, judges, prosecutors and other top officeholders.

It is not the opposition party alone that believes that the prosecution is biased in favor of the powers that be ― more specifically the incumbent president and his party. The belief is shared by many, who suspect prosecutors often turn a blind eye to influential people involved in corruption and other criminal cases.

Indeed, it is not rare for prosecutors to dismiss a case, only to reopen it under public pressure. One latest case involved a presidential aide who allegedly ordered officials in the prime minister’s office to spy on a civilian that had lampooned the president. The prosecution, which dismissed the case two years ago, reopened it later and arrested the presidential aide and other officials.

The root of the problem lies in the prosecution’s monopoly of the state’s right to institute criminal proceedings. In other words, the prosecution alone is authorized to decide whether or not to initiate and continue criminal proceedings.

Proposals have been made in the past to establish a new law-enforcement agency to rein in the all-powerful prosecution. But they have failed to survive strong opposition from the prosecution.

A similar bill, submitted by a lawmaker affiliated with the main opposition party earlier this month, is awaiting action in the National Assembly. It deserves earnest debate on the floor.

It would be naive to believe that corruption will be driven out of officialdom once presidential amnesty is restricted and a new prosecutorial office is established. But the least these institutional changes can do is give influential people a stronger warning against abusing their power for private gain.