This is a re-post of an essay I just wrote for The National Interest. I discuss the recent announcement at the 8th Workers Party to Congress to significantly modernize and expand the North’s nuclear and missile arsenal.

A lot was announced, but my inclination is to agree with Ankit Panda that the development of battlefield nuclear weapons is the most important announcement. I noted this in my comments to Ankit on Twitter: “These strike me as a battlefield leveler for NK’s military which is technologically far behind. Also South Korea is really dense in just a few places/cities, and it has a few highly vulnerable critical junctures, like the highway Route 1 running through the mountains or Busan port. Battlefield nukes would be ideal for disrupting these junctures.”

The full essay follows the jump:

North Korea recently convened the Eighth Congress of its ruling Workers Party. These are, of course, highly scripted affairs, but for outsiders, they offer one of the few windows into North Korean policy-making which we have. The speeches and reports released provide at least a general sense of where the North Korean elite sees the country’s economic development and foreign relations especially.

Much of this year’s focus on has been the proposed major expansion of North Korea’s nuclear capabilities. Updates and improvements include longer-range missiles, hypersonic missiles, and smaller, tactical nuclear warheads to supplement the larger weapons which provide the bulk on North Korean deterrence against the US and other foreign opponents. (For fuller technical details on the modernization, try here.) The political backdrop of justification is America’s unchanging ‘hostile policy.’

Politically, this is not very surprising in its broad strokes. Relations between the US and North Korea have been very poor for a long time, of course. North Korea explicitly sought nuclear weapons to deter the United States from attacking it. Northern nuclear negotiators routinely invoked the fate of Saddam Hussein of Iraq or Moammar Kaddafi of Libya as justification: had those leaders possessed nuclear weapons, the US would not have attacked them. This logic is almost certainly correct.

The timing at the end of US President Donald Trump’s term is also likely not a coincidence. North Korea achieved the ability to strike the United States with a large nuclear weapon in late 2017. It then paused the development and elaboration of its nuclear and missile programs, likely to see what might come of Trump’s effort to engage North Korean supreme leader Kim Jong Un in negotiation.

This pause was strategically wise. North Korea did not give up anything. No nuclear weapons or missiles were surrendered, but it did give Trump the illusion of progress and some breathing space to make a serious offer to the North. Trump never managed to offer concessions remotely commensurate to his demands though. The Americans repeatedly insisted on terms close to total disarmament in exchange for sanctions relief. This was wildly unbalanced in America’s favor – and Kim himself made analogously unbalanced offers in the North’s favor. Further, the North Koreans likely sensed, as much of the commentariat did over time, that Trump seemed more interested in the imagery and media coverage of the meetings than in the details of a deal. In the end, the talks simply withered away.

Now comes Joseph Biden as the new American president, and he is a well-known hawk on North Korea. As chairman of the Senate Foreign Relations Committee and vice president under former President Barack Obama, Biden cleaved to fairly establishmentarian approaches to the North. He advocated sanctions, deeper cooperation with South Korea and Japan, and pushing China to help rein in Pyongyang. This is not terribly imaginative; it basically follows the contain-and-sanction consensus on North Korea policy which has developed over decades in Washington. Nor is it dangerous or war-threatening, like Trump’s course in 2017; Biden is no bomber. But it does mean that US-North Korea relations will likely return to confrontational status quo which has characterized them for decades.

In short, the North probably held off on further nuclear and missile rollouts and elaborations after 2017 to see if Trump was serious in his outreach. He was not, and Biden is a pretty standard North Korea hawk. So now Pyongyang will return developing a modern, multifaceted program.

The military implications are less clear. As Ankit Panda notes, the move to tactical nuclear weapons is the most concerning. North Korea’s ability to deter a US regime change assault depends primarily on its ability to deliver a large nuclear weapon to the US mainland. That requires an intercontinental ballistic missile and a warhead of at least several hundred kilotons in yield. Such a weapon would parallel those built by the US and the Soviet Union during the Cold War to hold each other’s cities hostage and maintain peace through a balance of fear.

That worked during the US-Soviet stand-off, and we assume that this is the goal of North Korea too. And its developments before 2018 – larger warheads, missile of greater throw-weight – suggest that it sought this traditional deterrence relationship. This is obviously not a good development, but it is understandable. We know the logic behind such weapons procurement.

Tactical nuclear weapons are different. They have a much lower yield. Scenarios for them often include use on a battlefield or against extremely hardened underground targets. This is unnerving. For what purpose, then, would the North Koreans want such weapons? That the North Koreans provide no doctrinal statements on nuclear use or planning makes this question even more opaque:

One scenario floating for years on the most hawkish fringes of the analyst community is that North Korea actually wants nukes to bully South Korea into submission, not simply for defense. Another is that North Korea will at some point be so desperate for foreign exchange because of sanctions, that it will start proliferating its nukes and missiles for money. A third is that North Korea might actually use nuclear weapons on the battlefield in South Korea in the case of a war. North Korea’s military is large but obsolete, and South Korea has just a few, extremely dense cities and several critical infrastructure junctures in an otherwise mountainous country.

In each case, low-yield nukes fit the frightening script. This is something we will need to watch closely.