A prosecutor shamed National Assembly Speaker Park Hee-tae, speaker of the National Assembly, when he raided the offices of his secretaries for search and seizure on Thursday. None of his predecessors had faced such mortification since the Assembly was inaugurated in 1948.

But the problem is not just that he deserved the shame, as he was suspected of buying votes for his election to the chairmanship of the ruling party four years ago. More humiliation is yet to come if he tries to hide behind what he called his failing memory, instead of acknowledging or denying the allegations against him in unmistakable terms.

On returning from his overseas trip on Wednesday, he said, “My memory is faint because it is a case about an incident that happened four years ago. Moreover, there were five other important elections in succession.” He added at a news conference that, as an apology, he would not run in the April general election.

One of the questions about his remarks is why he offered an apology if he was not convinced that he sent cash in envelopes to lawmakers and party deputies, as suspected, in an attempt to buy their votes. Moreover, his decision not to run in the upcoming elections could not serve as an apology because he had already committed himself to not seeking his reelection before the money-for-votes scandal broke out.

Park lost an opportunity to control the damage by making a lame excuse. Instead, he should have immediately offered to resign as speaker and promised to surrender himself to the criminal investigation that is under way. His evasive action prompted the opposition Democratic United Party to submit a resolution calling for his resignation to the National Assembly.

He is also under mounting pressure from the ruling Grand National Party to tender his resignation. Its secretary-general said that what Park said at the news conference fell short of expectations and that “he should make a decision befitting his career as soon as possible.”

It appears to be a matter of time until the prosecutors’ office summons him for an inquiry. Before subjecting himself to a criminal investigation, he is called on to resign and, by doing so, help to keep the image of the legislature from being tarnished any further. That is the least that he must do.