Former President Lee Myung-bak is under siege on all sides. There are too many cases for which authorities and critics argue that he should assume ultimate responsibility that it may be inevitable that he comes under investigation. This leads us to several thoughts.

In some way, Lee, who occupied Cheong Wa Dae from 2008-2013 deserves retroactive scrutiny and punishment because what has been disclosed so far is enough to indicate that his administration committed serious misdeeds and illicit acts.

Gravest of all is the allegation that the Lee administration abused the nation’s top spy agency to strengthen and extend conservative rule.

The National Intelligence Service, whose top posts are now occupied by people close to President Moon Jae-in, is turning up one piece of evidence after another pointing to its massive interference in politics and domestic affairs.

Won Sei-hoon, who headed the NIS during the Lee administration, has already been jailed over the agency’s covert cyber operation aimed to bolster political base of conservatives and help Park Geun-hye win the 2012 election over Moon who was the liberal standard-bearer.

The NIS’ operation of the cyber team came to the fore shortly before the 2012 presidential poll that elected Park, but its details -- like the fact that the team had 30 units manned by as many as 3,500 people -- have just been made public.

An NIS task force looking into its own past activities also found papers containing a similar covert campaign against Seoul Mayor Park Won-soon.

The papers showed that the NIS was engaged in smear campaign against Park, who was a strong potential presidential candidate, on the internet and social media. NIS agents allegedly financed conservative civic groups that organized outdoor demonstrations and other smear campaigns against the mayor.

The target of such illicit operations was not limited to opposition politicians. The NIS under the Lee administration was found to have blacklisted artists, cultural figures and members of the media.

The existence of such a blacklist came to light in the wake of the investigation into the corruption scandal that ousted Park.

But the recent findings show that the Lee administration too had a blacklist of actors, movie directors, comedians, writers and singers to suppress progressive forces and curb criticism of government.

One shocking episode is that NIS agents even went on to manipulate and distribute a pornographic photo that portrayed an actor and an actress lying together naked. The nation’s supreme intelligence agency was acting like a bunch of crooks.

All these show that the NIS which had been a prime governing tool of the repressive rule of military dictatorships has yet to shake off legacy of the past.

There is no doubt that full light should be shed on all the cases and due punishment should be meted out for those who are responsible for the sake of preventing the NIS from repeating the same misdeeds.

There is one lingering concern, however: All the latest developments regarding the Lee administration may be part of the new liberal government’s political vendetta against conservative leaders.

Granted, it is usual – be it a liberal or conservative government -- for a new administration to condemn and penalize previous governments in the name of justice and correcting past wrongs.

But the antagonistic campaign toward Lee is too big. Besides allegations involving the NIS, relevant authorities have reopened investigation into defense acquisition programs and the four-river development project undertaken during the Lee government. There is enough ground for Lee and his aides to accuse the Moon administration of a witch-hunt.

Again, no one, including Lee, should never be spared from punishment if he had violated the law. But it is wrong too to seek undue punishment against him only because he was president.

Excessive and inordinate actions against Lee will draw a backlash from the former leader and the conservative bloc as a whole. Any such standoff and widening of the already serious national division is the last thing we could withstand at a time when the nation is struggling with daunting challenges, not least the North Korea crisis.