We took a look at the comparative effects of a conventional artillery attack and a nuclear attack on Seoul. North Korea has maintained the ability to inflict tens if not hundreds of thousands of fatalities on the South using inaccurate and labor-intensive but voluminous long-range artillery fire for decades. Nuclear weapons allow North Korea to maintain the threat of a countervalue attack on Seoul, while providing more flexibility than their current deterrent forces. Also, the probable reliance of the North Koreans on chemical weapons in a shooting war means their legacy “conventional” deterrent already stands a high likelihood of provoking nuclear retaliation by South Korea’s American ally.
Even given high rates of missile interception, nuclear weapons allow the North Koreans to accomplish with a few munitions what previously took hundreds of thousands. And antimissile defenses are not perfect. Not every missile will be hit, and not every hit will actually kill the warhead. The use of decoys and saturation salvos are likely tactics that would lower the intercept rate against North Korean missiles compared to those fired from Yemen in the linked article.
The nuclear deterrent is also more flexible. Nuclear-tipped missiles can threaten not only all of South Korea — including important ports like Busan and Pohang that are out of reach of long-range artillery — but also off-peninsula support zones such as Japan, Okinawa, and Guam. (North Korean nuclear ballistic missiles are probably useless against naval targets — they aren’t accurate enough and they can’t likely get target-quality data anyways). They even open up the possibility of retaliation against the US mainland.
Ranges of North Korean missiles, 2016
Nuclear weapons can point not only to the south but to the north. The North probably doesn’t consider China a threat in the same way they do the South Koreans or the United States, but there’s intents and then there’s capabilities, and China has a lot of capability sitting on the other side of a comparatively lightly-defended border. If Kim thinks he’d ever like to do something the Chinese might not like — such as Korean reunification — he’ll probably feel a lot more comfortable being able to announce that any invasion would or could be met with nuclear retaliation.
The point is that the North’s nuclear weapons can replace their conventional deterrent while adding a lot of capabilities that howitzers and artillery rockets can’t, and it probably isn’t even costing them that much. Again, North Korea can spend ~10% of its current defense budget on its nuclear program to replace an entire artillery corps, at the absolute minimum, and may set the stage both militarily and politically within the North for an even further drawdown of the North’s bloated conventional forces, a legacy of Kim Jong-Il’s “military first” economic policy.
North Korea isn’t the only country which has ever made this calculus. The United States made a similar, deliberate choice in the 1950s to counter Soviet forces in Europe with nuclear weapons on the grounds of cost-effectiveness. Stephen Schwartz of the Brookings Institution, who wrote the Atomic Audit book I cited in the last post, believes that this was ultimately false— however, he attributes this to the development of an excessive diversity of warheads and delivery systems, pork barrel politics, and mismanagement of the targeting process, NOT to the cost of nuclear weapons themselves. North Korea, even if they are totally unaware of this history, is constrained by its poverty into not investing trillions of dollars into overkill. One warhead type mounted on a few dozen missiles of various ranges — culminating in submarine-launched and intercontinental types — will suit them fine.
All of these benefits also suggest that North Korea’s nuclear weapons aren’t going away. The “international community” has already “allowed” Pakistan, Israel, India, and the People’s Republic of China to build nuclear weapons. The examples of Pakistan and Israel are particularly instructive: in both instances, a relatively small state threatened by larger neighbors (India, the Arab states) maintains a nuclear deterrent as an equalizer. In many ways this asymmetric viewpoint is a more natural use of nuclear weapons than as one more asset in the arsenal of wealthy states with large militaries.
God created the nations, but J. Robert Oppenheimer made them equal.