North Korea is boasting about the "successful launch of the new-type tactical guided weapon system" that is capable of "enhancing the efficiency in the operation of tactical nukes." That means the North could now be capable of hitting Seoul with so-called "tactical" or smaller nuclear weapons that could be used in conventional theaters of battle. Russia has threatened Ukraine with the use of such weapons, and North Korean leader Kim Jong-un ordered scientists to develop tactical nukes in January of last year. Unlike intercontinental ballistic missiles, tactical nukes are aimed squarely at South Korea. His sister Kim Yo-jong's threat to leave the South Korean military "little short of total destruction and ruin" could become a reality if North Korea has both tactical nukes and missiles to deliver them.

The South Korean military relies on the "kill chain" of preemptively detecting and eliminating North Korean attacks and the Korea Air and Missile Defense (KAMD) to shield itself. But holes in the strategy are gaping wider by the day. It is only theoretically possible to launch preemptive strikes against an enemy armed with nuclear weapons -- but no matter how tight the defense, even one nuclear warhead falling on South Korean soil would spell disaster.

Weapons can only be countered with weapons of the same caliber. This has been the rule throughout human history. A nuke can only be deterred with nuclear weapons. Even the most powerful conventional warhead is only 1/10,000th the power of a nuclear warhead. NATO members who lack nuclear weapons have either formed pacts with the U.S. or entrusted the organization to mobilize such weapons in emergencies. The National Defense University under the U.S. Department of Defense proposed the sharing of nuclear weapons with South Korea in a 2019 report, and late last year, two U.S. professors wrote in an op-ed that Washington should support Seoul's acquisition of nuclear weapons to keep Pyongyang and Beijing in check.

South Korea's regional neighbors are either nuclear powers or have the capability to become one quickly. Russian President Vladimir Putin has already threatened to use nuclear weapons in Ukraine, but a nuclear-armed state would not have been invaded in the first place. Kim will continue to threaten South Korea with nuclear weapons.

Efforts must continue to achieve North Korean denuclearization. But it is best to be realistic and come up with concrete preparations because anything else would compromise national security. The only way to maintain peace is to gain superior firepower.

[Read this article in Korean]