The way past and incumbent governments alike have dealt with the deployment of a US missile shield system to counter threats from North Korea shows how foolhardy and senseless the leaders of this country are.

The Moon Jae-in administration’s decision last week to deploy four additional interceptor launchers for the Terminal High Altitude Area Defense battery was only the latest in a series of flip-flops the South Korean government did. Moon took the action in response to the North’s test-launch Friday of a second intercontinental ballistic missile in 24 days.

The decision -- which paved the way for full-fledged operation of the THAAD battery of six launchers -- came only 15 hours after the Moon administration had announced plans to assess the system’s environmental impact, which could take up to 15 months.

In other words, the government made a decision that could delay the completion or even cancel deployment of the THAAD battery without considering what has become ever-present threats from the North’s missile capabilities. That is simply ridiculous, all the more so as intelligence and media reports predicted an impending ICBM launch by the North.

The root cause of the mix-up over the THAAD system was set in place during the Park Geun-hye administration. It should have kept it a military secret or, if it had decided to make it public, it should have thought about its impact on domestic politics, residents and relations with China. The Park administration was not up to doing that.

In addition, the Park administration gave in to opposition from residents of the originally designated site for the THAAD battery, and moved it to a golf course run by the Lotte Group. What we see now is that residents from the golf course area – emboldened by what their neighbors achieved -- are blocking passage of military vehicles to and from the site and Lotte has become a prime target of China’s economic retaliation.

After Park’s impeachment, it was Moon’s turn to complicate matters further. Like other liberals, Moon, then a leading presidential hopeful, initially opposed the deployment of the US missile shield.

In order to reach out to centrist and mild conservative voters, he endorsed the system as the voting day approached. He was straddling the fence, however, as he attached conditions, such as the implementation of “legitimate” process.

After winning the election, Moon needed not cater to all. He took issue with the arrival of four launchers -- two were already on the golf course under the Park administration’s decision -- alleging that the Defense Ministry kept him in the dark intentionally. The truth is their arrival had already been reported by the local media.

The “shock” Moon expressed at that time was largely seen as a move to justify his -- and the liberal camp’s -- hope to delay or even thwart full deployment of the THAAD battery.

No wonder Moon’s rebuke of the Defense Ministry for its failure to report the arrival of the four launchers, along with his emphasis on “legitimate process” for stationing the THAAD battery, made the US suspicious of the Seoul government’s position.

Then during his visit to the US in June, Moon told Congress leaders that South Korea would not reverse the decision to host the THAAD system. One cannot but be confused about what is on his mind.

Having read so far, you could presume that Moon wanted to buy time -- the Friday’s announcement on a full environmental survey was one piece of evidence -- and hopefully resolve the North’s nuclear and missile threats through dialogue, which could obviate the need for the THAAD system. If so, he is naive.

The missile interception system is not the only thing that can deter the North’s rapidly growing nuclear and missile menace. But the way South Korean leaders take on the issue is a good barometer of whether they will screw up a matter that can seriously affect national security. The time has come to end this folly once and for all.