On Thursday, more than 90 lawmakers affiliated with the Democratic Party abandoned air-conditioned conference rooms in the National Assembly and gathered for a protest rally in the scorching Seoul Plaza. Was it was going to be a prelude to raging anti-government street demonstrations or a one-time occasion to vent the anger of a frustrated opposition party?

The outdoor protest was directed against the ruling Saenuri Party, which the lawmakers said was obstructing a scheduled parliamentary investigation into the National Intelligence Agency that was accused of meddling in domestic politics. Undoubtedly, the opposition party was hoping its rally would jump-start mass outdoor protests.

It goes without saying that the rival parties should pursue conflict resolution within the walls of the National Assembly as practitioners of representative politics. But the Democratic Party literally took it to the streets when it held an outdoor rally in its direct appeal to the public for support. In doing so, however, it acknowledged it lacked sophisticated negotiating skills that were demanded of representative politics.

That having been said, the opposition party had good reason to claim that it was virtually driven out of the National Assembly. It said it ran out of patience when it was negotiating with the ruling party on the issue of bringing key figures to take the witness stand ― Won Sei-hoon, former intelligence director, and Kim Yong-pan, a former Seoul police commissioner.

Won was accused of ordering his agency to smear the opposition presidential candidate ahead of the December presidential election. Kim Yong-pan was accused of covering up the deletion of online comments against the opposition candidate by the intelligence agency. The parliamentary investigation would be virtually meaningless without their testimony.

But the opposition party must be held accountable for a stalled investigation, at least, to the extent that it failed to elicit support from the ruling party. Instead, it angered the ruling party when it used irresponsible and provocative rhetoric against President Park Geun-hye. If it wanted cooperation from the ruling party, it should have refrained from saying that Park would have to be impeached and that the result of the presidential election be nullified. Simply put, it did not focus on what it was aiming for.

The rival parties have already wasted a lot of time. As they continue to fight over key issues, the deadline for the investigation is fast approaching. If no agreements are to be made during the next few days, there will be no meaningful investigation, if any at all. The 45-day period of investigation is set to close on Aug. 15.

Should the investigation come to an end without shedding any light on the allegation against the intelligence agency, it would disappoint many of those who believe the intelligence agency must be kept out of domestic politics and give rise to a third party at the expense of the Saenuri Party and the Democratic Party. If they are to control the damage that is already done, the rival parties will have to hasten to agree on witnesses and start a parliamentary investigation in earnest immediately.