The recent Supreme Court ruling on a progressive, leftist teachers’ union is hard to understand.

The Korean Teachers and Education Workers Union was outlawed by the previous administration under former President Park Geun-hye.

The Park government took the action based on an article in the enforcement ordinance of the teachers’ labor union law. The article requires the government to outlaw a labor union if it refuses to follow a government order to comply with the law.

The union accepted nine fired teachers as its members in violation of the law, which specifies that only incumbent teachers can become members of their union.

The Park administration ordered the union to correct its bylaw accepting fired teachers as members, but the union refused, which led to the government outlawing it in accordance with the ordinance.

However, the top court under Chief Justice Kim Myeong-su, appointed by President Moon Jae-in, ruled to the effect that labor rights can be restricted only by law, not by enforcement ordinance. It said the article in the ordinance was invalid because an important matter such as outlawing a labor union should be decided by a law, not by an enforcement decree.

The related law says the union is illegal, but the top court took issue with its enforcement ordinance, ignoring the law on which it is based.

According to the top court’s ruling, the union violated the law but is a legal group. This sounds contradictory. The top court’s ruling ignored the system of existing law, effectively infringing upon the domain of legislation.

In 2015, the Constitutional Court ruled the article in the ordinance constitutional. The lower courts ruled that the government acted lawfully in outlawing the teachers’ union.

Then the judiciary did a complete U-turn. If there is anything that caused the about-face, it would have to be that most of the Supreme Court seats were filled with Moon appointees supportive of his administration.

The dissenting opinions of the two justices who believed it was legal to outlaw the union sound sensible.

“The related articles in the law are so obvious that there is no room to interpret it differently,” they said. “The majority opinion does not interpret the law as is, but effectively creates a new one.”

The Supreme Court ruling gives the impression that it maneuvered around the legal system to side with the union intentionally.

When it was launched in 1989, the union professed to realize “true education.” But it got away from that vision, degenerating into a group that engages more in political issues and seeks to inculcate leftist ideology in students.

Moreover, the nine fired teachers accepted by the union were convicted of intervening in education superintendent elections, violating the national security law and leading illegal rallies. And yet the union refused to take measures as ordered by the government. Nevertheless, the Supreme Court opened the way for legalizing it.

The ruling appears to have followed a consistent tendency of the top court’s recent decisions. It quashed lower-court convictions of two members of the ruling Democratic Party -- Seongnam City Mayor Eun Soo-mi and Gyeonggi Province Gov. Lee Jae-myung. Eun and Lee were convicted of violating the political campaign fund law and the public office election law, respectively.

Appellate courts meted out sentences severe enough to strip them of their public offices, but the top court saved them.

Regarding the appeals court decision to raise Eun’s fine, the Supreme Court took issue with the petition of appeal filed by the prosecution. It said the prosecution had not specified its reasons for the petition. This judgment seems irrational.

In throwing out Lee’s conviction, the Supreme Court gave absurd reasons for its decision. Lee -- often seen as a prospective presidential candidate -- was accused of lying in a TV debate among candidates for the last presidential election, but the top court ruled that he did not give false information because he did not lie “actively.” Are there active lies and passive ones?

Naturally, these rulings invite critical online comments such as “a predetermined ruling,” or “not guilty if you are on our side but guilty if you are not.”

The Supreme Court under Chief Justice Kim looks like a partisan group for the ruling camp, rather than the last bastion for the rule of law. It must interpret law as is.