The arrest of former President Lee Myung-bak, while adding to the already shameful history of Korean presidency, should be a reminder of several things. The first is the need to revise the Constitution in order to curb the power of the president.

Now locked up in a detention center in Seoul, Lee is the fourth former president to face such a fate. Chun Doo-hwan and Roh Tae-woo spent time in jail for corruption and mutiny charges in 1995, and Lee’s successor Park Geun-hye has been behind bars for about a year on corruption and influence-peddling charges.

In the case of Lee, there are some grounds to the argument that the state prosecution’s massive investigation was politically motivated. But the charges raised against him and people close to him showed that the Korean presidency is very much vulnerable to corruption and other misconduct.

The need to address the problems of what is called an “imperial presidency” has been raised since the impeachment of Park about one year ago. That led to calls to revise the Constitution, which was amended in 1987 in the wake of a pro-democracy movement and is outdated in many respects.

Most of all, the 1987 Constitution focused on ending successive military-backed dictatorships, and resulted in the revival of the popular vote for the presidential elections as well as the introduction of a five-year single-term presidency. The 1987 basic law, however, failed to institute enough measures to restrict the power of the president.

President Moon Jae-in, who was elected in the aftermath of Park’s ouster, pledged during the election campaign that he would end the imperial presidency by changing the Constitution.

Moon outlined his bill to amend the basic law last week, but it fell far short of meeting people’s expectations. Some of its clauses met criticism even from his political allies, including National Assembly Speaker Chung Sye-kyun.

Chung especially took issue with Moon’s bill for proposing the adoption of a presidential system in which the president is allowed to serve two consecutive four-year terms, without prescribing effective measures to limit the power of the president. As the speaker said in a published interview, it is not reform, but a change for the worse because it could allow a president with excessive power to serve up to eight years.

Indeed, the bill contains only superficial measures regarding the reduction of the power and authority of the president.

For instance, the bill dropped the stipulation that the president serves as the “head of state.” The fact is that it is only a nominal title that has little to do with the exercise of presidential duties and rights.

The bill also made some cosmetic changes to presidential appointments of powerful agencies. It calls for the president to give the right to appoint three of the seven commissioners of the Board of Audit and Inspection to the National Assembly and have the justices of the Constitutional Court elect its chief justice among themselves.

There were no changes, however, to reduce the president’s control of powerful agencies, including the state prosecution.

The bill also rejected the opposition’s demand that the prime minister, who is now picked by the president, be nominated by the National Assembly.

The bill is to be submitted to the National Assembly on Monday despite public criticism about Moon’s unilateral move to revise the Constitution. However, what is fortunate is that it has no chance of being passed by the parliament due to objection from opposition parties.

But with the presidential bill in the parliament, ruling and opposition parties cannot drag their feet any longer, and should start discussions about how and when to revise the basic law. Their utmost concern, of course, should be instituting ways to hold in check the power of the president.