The controversy over the alleged pro-North Korea lawmakers of the left-wing United Progressive Party has escalated into a virulent ideological dispute between the ruling Saenuri Party and the main opposition Democratic United Party.

The escalation was sparked by DUP Rep. Lim Soo-kyung, a former high-profile student activist who became a lawmaker on a proportional representation ticket.

Lim recently insulted North Korean defectors in the South by calling them “traitors.” She apologized to the defectors for her careless remarks. But more than 200 civic groups urged the DUP to take disciplinary action against her as she revealed her true identify ― a “blind North Korea follower.”

The novice lawmaker provided ample ammunition to the ruling party. Yet another DUP lawmaker provided even more. Rep. Lee Hae-chan, a former prime minister who is running to become the party’s new leader, caused a stir by criticizing a Saenuri bill on enhancing North Korean human rights.

Lee called the bill a “diplomatic discourtesy,” asserting that the South should not attempt to intervene in the North’s human rights issue through legislation.

Lee’s ill-advised criticism of the bill fueled the ruling party’s offensive on lawmakers suspected of sympathizing with Pyongyang. Rep. Hwang Woo-yea, the party’s new leader, even suggested that lawmakers like Lim and Lee should be referred to a parliamentary process where the qualifications of lawmakers would be reviewed to weed out ideologically problematic members.

The review process mentioned by Hwang was in fact proposed to deal with the two UPP lawmakers ― Reps. Lee Seok-gi and Kim Jae-yeon ― who were found to have become proportional representation candidates for the minority party through rigged intra-party primaries.

Rep. Park Jie-won, the floor leader of the DUP, at first expressed his support for the ruling party’s plan to expel the two UPP lawmakers through the review process. Yet he changed his stance as it could be used for DUP lawmakers accused of siding with Pyongyang.

As the Saenuri Party stepped up its accusations of opposition parties for failing to punish their allegedly pro-North Korea lawmakers, the DUP countered by asserting that the ruling party was invoking McCarthyism to paint its lawmakers red, the color associated with North Korea.

Park denounced the ruling party for attempting to cover up all the wrongdoings it has committed by fueling a malicious, all-consuming ideological debate.

There is a point to the DUP leaders’ assertions. The ruling party is undoubtedly keen to escalate the ideological dispute to highlight the weak points of the main opposition party, while keeping its own weaknesses from being exposed.

Saenuri’s offensive is also motivated to frame the coming presidential election in December as a battle between pro-Pyongyang forces and those committed to defending liberal democracy.

Yet the DUP needs to realize that some of its arguments are not convincing. For instance, the party’s leaders all claim that the North Korean human rights bill is an attempt to interfere with the North’s domestic affairs.

This ignores the fact that the U.N. Human Rights Council has adopted a resolution on North Korean human rights every year since 2003 to express concerns about the serious situation in the North and urge the isolated state to redress human rights violations.

It should be brought home to the party that public sentiment on the opposition parties’ stance regarding North Korea has changed following the controversy over the alleged pro-Pyongyang UPP lawmakers.

Now a majority of the public want opposition parties to openly criticize the North’s misguided policies, such as the blind pursuit of nuclear weapons, and its anachronistic behavior, for instance, the transfer of power from father to son. The DUP can keep silent on these issue at its own peril.

The Saenuri Party also needs to resist the temptation to ratchet up its rhetoric against the allegedly pro-North Korea lawmakers. Its offensive, if pushed too far, can backfire, as it will be seen as a nasty McCarthite smear campaign.

More importantly, an ideological dispute can become a vortex that sucks everything into it. If a black-white ideological dichotomy prevails, there would be no room for policy debates. Political parties should try to prevent such a situation from taking hold.