The National Assembly has launched an ad hoc panel entrusted to amend the Constitution, a job the legislature should have done much earlier.

The Special Committee for Revising the Constitution, which elected Lee Ju-young of the ruling Saenuri Party as its chairman Thursday, plans to hold the first of a series of public hearings next week.

In the months to come, the committee -- and advocates of rewriting the basic law as a whole -- will face a lot of hurdles in their efforts to come up with an amendment bill. But the fact that the panel has been put into full operation itself should be noted because it is the first time that the parliament has formed an ad hoc panel to revise the basic law since it was last amended three decades ago.

Adding to the positive development is that Moon Jae-in, the leading presidential contender, who had been the most ardent critic of the proposal to revise the basic law, has eased up on his opposition.

Moon, believing that the Choi Soon-sil scandal has greatly boosted his chances of winning the election, had opposed any talk of a constitutional amendment, accusing proponents of attempting to divert public attention away from the anti-Park protests.

Moon’s stance drew criticism that he was overlooking an issue of great national importance in pursuit of personal power. Indeed, all other major political parties and presidential contenders, including former UN Secretary-General Ban Ki-moon and Ahn Cheol-soo of the People’s Party, support the revision of the Constitution, which was last amended in 1987 in the wake of the pro-democracy movement that ended a chain of dictatorships.

Criticism against Moon reached its peak when it was made public last week that the party’s think tank authored a report on “how to foil” the move to revise the Constitution, which it said could jeopardize Moon’s presidential campaign.

But what seems to be Moon’s strategic retreat does not guarantee that the parliamentary panel will be able to pull off an agreement at an early date.

One of the most contentious issues will be the when a constitutional change happens. With the fate of the parliament-impeached President Park Geun-hye still uncertain, the timing of the revision is part of a complicated political equation.

Committee Chairman Lee Ju-young said he hopes to revise the Constitution before the next presidential election, even if Park’s impeachment is upheld by the Constitutional Court, which would mean the nation will be given only two months before electing a new president. Some politicians, including Sohn Hak-kyu, support the proposal.

But a majority of presidential hopefuls, including Moon and Ahn, suggest that the next election be held under the current Constitution and that the Constitution be revised in 2018 or 2019 at the latest.

To be fair, it wouldn’t be easy to revise the basic law before the election if the Constitutional Court decides to remove Park from office. Moreover, there are different views about whether the next president should shorten their term of office to pave the way for a constitutional amendment.

Then comes another contentious issue: What should be the scope of the changes to the basic law? Some argue that, considering the urgency and lack of sufficient time, the discussion this time should be limited to changing the power structure -- which is now based on a five-year, single term presidency.

The three main alternatives are allowing the president to serve up to two four-year terms, a dual executive or semi-presidential system in which some of the key presidential power is given to the prime minister, and a parliamentary Cabinet system.

It is true that power structure would be a key issue in discussions on a constitutional amendment, but other parts of the basic law are no less important, many of which are outdated. In this regard, the parliamentary panel was well-advised to install four subcommittees to deal with clauses on basic rights, economy, unification, local autonomy and others.

All in all, the utmost job of the committee is to enliven and hasten discussions on the major issues involving a constitutional revision, including its scope and timing. It is needless to say that the committee needs input from outside experts who are free from partisan interests.