In general, criticizing others should be backed up by facts. In particular, blaming a top leader of another country for a war is extremely dangerous, if not crazy, unless such a claim is based on a mountain of verified facts.

Top leaders of the ruling Democratic Party of Korea, including its presidential candidate Lee Jae-myung, did not follow this simple principle, and made unbelievably incendiary remarks targeting Ukrainian President Volodymyr Zelenskyy. They falsely claimed the war with Russia started because of Zelenskyy’s inexperience.

Understandably, a number of online communities at home and abroad are raging about the thoughtless remarks, with many users slamming the key members of the ruling party for grossly misinterpreting the geopolitical background of the Ukraine war -- a war that was started by Russia and its president Vladimir Putin.

Lee Jae-myung said at a televised debate Friday evening: “Since a novice politician with only six months of experience became president of Ukraine, publicly announced NATO membership and provoked Russia, (the two nations) eventually clashed.”

Lee said Russia’s invasion into Ukraine’s territory deserves strong condemnation, but the Ukraine conflict is “a clear case in which a failure of diplomacy results in a war.”

What followed was Lee’s attempt to depict his rival Yoon Suk-yeol, the presidential candidate of the main opposition People Power Party, as a “novice politician” who is also “too rough and violent.”

The parallel with the Ukraine president is unmistakably clear. Lee suggested that if Yoon gets elected, South Korea might follow a similar path toward a war with North Korea, due to his inexperience in diplomacy.

But the fallacy of the comparison is too plain to miss. If a war breaks out, according to Lee’s logic, the leader of the nation under invasion -- rather than the aggressor -- should be blamed for starting a war.

The extensively shared comment by Lee is not so diplomatic in tone and content, especially for a scandal-laden politician who is under fire for his “violent” language toward his own relatives in the past.

Alarmed by a firestorm of criticism, Lee issued an apology but suffered a severe damage to his public image, with the make-or-break election slated for March 9. Despite Lee’s apology, it is deeply worrying that his strange framing of the Ukraine crisis is not a slip of the tongue. Choo Mi-ae, a former justice minister and honorary chief of Lee’s campaign team, posted on social media as follows: “A comedian-turned president in Ukraine bluntly announced a push to join NATO, which invited an uncontrollable crisis.” The veteran politician, widely regarded as a key leader of the ruling party, called Zelenskyy “an amateur president” with no diplomatic experience, and who provoked Russia through his “half-fledged leadership.”

Choo did not forget to steer her criticism of the Ukraine president toward Yoon Suk-yeol, claiming that his “provocative” comment in favor of additional deployment of Terminal High Altitude Area Defense could touch off geopolitical risks.

The ruling party, led by President Moon Jae-in, has been trying to avoid provoking Pyongyang, a stance that is being attacked by critics who call for more assertive responses to the isolated regime’s continued test firing of missiles.

Rep. Park Yong-jin, co-chairperson of the ruling party‘s election campaign team, also shares Lee and Choo’s view. “The Ukraine leader became president thanks to brief popularity, and he was a comedian,” he said Friday. “Russian President Putin is hostile toward the Ukrainian president. Ukraine has lost its territory and its people are entangled in a war. We cannot put the fate of a nation on a briefly popular person.”

It is deplorable that Lee, Choo and Park not only have a misguided perception about how war breaks out, but also hold a deep prejudice against a specific occupation. The so-called top leaders of the ruling party must do sincere soul-searching about their controversial remarks and bear in mind that there should be a limit, even in making negative comments.