Opposition parties submitted a motion to impeach President Park Geun-hye, Saturday, vowing to get it through a full session of the National Assembly on Friday.

The motion -- the second of its kind after the one against President Roh Moo-hyun in 2004 -- is the first legal, parliamentary action taken against Park in connection with the influence-peddling and corruption scandal that has been shaking the nation for more than six weeks.

But the planned parliamentary vote, which otherwise should help the extended political crisis end quickly, is shrouded in a wealth of uncertainty. Most of all, no one can be sure whether the vote will proceed as scheduled, and if so, whether it could attract enough votes to halt Park’s duties and send the case to the Constitutional Court.

All players in what has become a complicated political game -- not least Park, the opposition parties and ruling party -- have their share of responsibility for the uncertainty. But it would be safe to say that the nonmainstream members of the ruling party -- who can sway the vote -- are casting the darkest clouds over the fate of the impeachment bill.

The ruling Saenuri Party -- where a severe internal feud has pitted Park loyalists against nonmainstream members over the president’s fate -- had managed to agree on the position that she should voluntarily step down from her post by the end of April and the next presidential election should be held in June.

But after the three opposition parties submitted the impeachment motion, cracks surfaced even in the anti-Park faction. Moderates like former party leader Kim Moo-sung insist that Saenuri members should not support impeachment if Park agrees to resign by April.

But hard-liners like former floor leader Yoo Seong-min argue that Park’s promise was insufficient and that they would vote for impeachment in the absence of an agreement with opposition parties on Park’s future.

In view of the fact that the opposition -- which, along with seven independents who signed the impeachment bill -- controls 172 seats, it needs at least 28 votes from the ruling party. The apparent about-face by Kim and other moderates certainly lowers the chances of impeaching Park.

Moreover, there is the likelihood that Park -- in order to avoid impeachment -- may state her acceptance of Kim’s demand. Park’s aides are already floating the idea of Park meeting Saenuri members and holding a news conference.

For now, the opposition parties are united in pushing ahead with the impeachment vote regardless of the positions of Saenuri’s anti-Park faction. They have grounds to do so: A majority of people -- as demonstrated Saturday in what was believed to be the largest-ever street protest in Korea -- want Park to resign immediately and unconditionally, and if Park remains defiant, impeachment is the only legal way to halt her duties as president.

But the reality is that the impeachment bill cannot be passed without votes from Saenuri members. By ignoring this reality and rejecting negotiation with the ruling party, the opposition camp runs the risk of aborting the impeachment vote.

There seem to be some political calculations behind the opposition’s position: By filing the impeachment bill, they could say they met the demand of people who want Park’s immediate ouster. They also may well believe that that they do not have much to lose even if the impeachment motion is voted down, because the ruling party would bear the brunt of the public denunciation. That would be an additional boon to them ahead of the presidential election.

But the parliament’s failure to impeach Park would be disastrous. Most of all, it may further embolden the ever-defiant Park and her loyalists, which in turn would add fuel to the already boiling public enragement. That would make the situation more chaotic.

The rival parties should sit together right away to forge an agreement before the impeachment vote. Their agreement should be either getting the vote passed by the parliament or setting up a package of steps on Park, including setting a date for Park’s departure and installing immediately a National Assembly-nominated prime minister who will take over most of Park’s powers.