As with other major political events, when and how are important in amending the Constitution, which was last revised in 1987 and is outdated in many respects.

Last year, there was strong consensus about when to revise the basic law, as seen by the fact that all major presidential candidates for the May election agreed to put an amendment bill to a national referendum alongside local elections on June 13 this year.

That reflected the public sentiment that the Constitution, which gives the president too much power, was partly to blame for the massive corruption scandal that resulted in former President Park Geun-hye’s impeachment and that the problem should be addressed as soon as possible.

Regarding how, there was no doubt that the National Assembly would take the lead in writing the amendment bill supported by a majority of people.

Now only three months away from the elections, it seems that revising the supreme law by June 13 and on the initiative of the National Assembly are implausible.

The biggest problem is that the National Assembly has made little progress since it launched a panel in late 2016, after the legislature impeached Park over the corruption and influence-peddling scandal.

While both the ruling and opposition parties are to blame for the lack of progress, the main opposition Liberty Korea Party and its leader Hong Joon-pyo were the biggest obstacles to constitutional revision.

During the presidential campaign, Hong had promised to complete constitutional revision by the local elections day, but he has changed his position, insisting that more time is needed.

It is obvious that Hong and his party do not want to hold the national referendum on the day of the local elections because it would raise voter turnout, especially among the younger generations, which usually works against conservative candidates.

With time running out and minor opposition parties, such as the Bareun Future Party and the Democratic Peace Party, joining forces with Hong’s party, President Moon Jae-in is pushing for a government-led revision of the Constitution.

Moon’s initiative is based on the stipulation of the Constitution that either the president or a majority of lawmakers in the National Assembly can propose its amendment.

Moon appointed a special advisory panel to draft an amendment bill to be sent to the National Assembly under his name. The panel wrapped up its work and presented Moon with a bill Tuesday.

There are many clauses and articles in the bill that need to be debated, but the most noticeable thing is that it opted for a presidential system in which the president is allowed to serve up to two successive four-year terms of office.

The proposal is favored by a majority of Koreans -- as shown by public opinion surveys -- but there are more options, like a semi-presidential system in which the president elected by popular vote and the prime minister picked by the National Assembly share power or a parliamentary Cabinet system. There will be more and more contentious issues, which means time is running out to meet the June 13 deadline.

Opposition parties contend that the president -- in ignorance of the parliament -- is pushing for constitutional revision on his own terms. They also contend the president’s bill lacks sufficient measures to curb the president’s power, one of the key factors behind the need to revise the basic law.

Their arguments, however, have no grounds. They are the ones who dragged their feet.

Given the number of parliamentary seats controlled by each party, there is little possibility of Moon getting his bill through the parliament without the consent of the opposition, but his move should be credited for creating momentum to revise the Constitution at an early date.

Speaker Chung Sye-kyun, a strong advocate of June 13 as the date for a national referendum, suggested that a later date for the referendum could be picked if the rival parties reach a compromise on an amendment bill. Chung’s position may reflect the reality.

But it is still too early to resort to “Plan B.” Both Chung and Moon should strive further to persuade the opposition parties.