President Moon Jae-in told CNN in an interview Thursday, “I do not agree that South Korea needs to develop our own nuclear weapons or relocate tactical nuclear weapons in the face of North Korea’s nuclear threat.”

Despite his dismissal of the possibility of deploying nuclear weapons in the South, people cannot help but question whether there are any other weapons but nukes that can defend against the North’s nuclear weapons.

Those who argue for the redeployment of US tactical nuclear weapons or South Korea’s own nuclear armament do not mean the country should use nukes. However, it is an undeniable truth that nuclear weapons can be deterred only by nuclear weapons.

The reason why the South is currently under the US nuclear umbrella is that countering nukes with nukes is inevitable to achieve a military balance.

Suppose there are no US troops in South Korea. If the North threatens to explode a hydrogen bomb over Seoul, how will the South cope with the threat?

Moon said in the interview, “To respond to North Korea by having our own nuclear weapons will not maintain peace on the Korean Peninsula and could lead to a nuclear arms race in Northeast Asia.”

Peace on the peninsula is not guaranteed because of North Korean nuclear threats. The inter-Korean military balance has been disrupted by the North’s nuclear weapons and conventional weapons cannot beat nuclear bombs.

It is irresponsible for the South Korean leader to assert that his nation will not have the means to deter nuclear weapons that threaten the lives of the people he must protect.

Pyongyang justified its nuclear program by arguing that it was threatened by US nuclear weapons. Now that it is a de facto nuclear state, it often mentions the unification of Korea under its rule.

Peace on the peninsula will not be maintained unless the South deters the North from firing its nuclear missiles toward the nation.

Stating categorically that any nuclear weapon -- strategic or tactical -- has no place in South Korea in the face of North Korea’s nuclear weapons will only fuel people’s anxiety over national security.

A Gallup Korea poll conducted after the North’s sixth and strongest nuclear test on Sept. 3 found that 60 percent of the respondents favor South Korea possessing nuclear weapons, with 35 percent opposed.

Moon’s warning that nuclear weapons in the South could lead to a nuclear arms race is hardly convincing and makes him sound like the leader of a third country.

It is hard to understand how a nuclear arms race could happen in Northeast Asia even if US tactical nukes are deployed in the South. North Korea, China and Russia are already armed with nuclear weapons.

The possible presence of nukes in the South would be more advantageous to maintaining its security than the rejection of them in the face of the North’s nuclear weapons.

The least the South Korean president should do about nuclear deterrence is to maintain strategic ambiguity.

What available means would be left if the president refuses the possibility of choosing a special countermeasure when the worst case happens?

Of course, it would not be a smooth process for the South to have its own nuclear deterrence. As China and Russia would oppose it strongly, it is questionable whether the US would deploy tactical nuclear weapons.

Nevertheless, the South must be able to do what it needs to do to defend itself. Under nuclear threats, security should come before anything else.

North Korean leader Kim Jong-un probably knows that a nuclear attack on the US amounts to an act of suicide. In a nutshell, the target of its nuclear weapons would be South Korea.

Assertive opposition to the existence of nuclear weapons in the South is not strategically wise. The South Korean president’s foremost responsibility is to maintain national security.

Before rejecting nuclear weapons outright, he should answer this question, “What will the South use to deter the North’s nukes?”