Under the cover of darkness in January 1968, 31 members of an elite North Korean special forces team slipped through the heavily fortified Demilitarized Zone and into South Korea. The team’s objective was as simple as it was daring: fight their way over rough terrain amid sub-zero temperatures, reach the South Korean presidential residence, and assassinate President Park Chung-hee. Over two days, the commando unit evaded ROK forces, reached the presidential residence known as the Blue House, and got within 100 yards of their ultimate target before being engaged by South Korean guards. 92 South Koreans, including dozens of civilians, died in the ensuing gunfight that lasted most of the night.  Their raid might have been successful but for one fatal flaw in the operation. Soon after this elite unit infiltrated South Korean territory, they stumbled across a group of civilians camping in the woods near the DMZ. Rather than neutralize the individuals who had compromised their position, the North Korean forces detained their southern brethren, treated them to an extended lecture on the virtues of communism, and set them free. These civilians were not converted and soon alerted South Korean authorities to the presences of a North Korean unit on ROK soil.

This episode is illuminating for a variety of reasons. First, it exemplifies the extent to which the government in Pyongyang was and remains committed to terrorism in order to advance its interests. Second, it revealed the ideological zealotry of North Koreans in defense of Juche. The intervening decades have not done much to temper either characteristic.

This certainly wasn’t the last time that the North would attempt to decapitate the South Korean government through terrorism. While on an official visit to Burma to commemorate the death of Aung San in 1983, a series of bombs expertly concealed in the roof of a ceremonial pagoda exploded and killed 21 people, including a series of ranking ministers of the ROK government. The North is not above targeting civilians to achieve its ends, either. In 1987, a bomb exploded aboard Korean Air Flight 858, killing all 115 on board. The North Korean agents responsible for that attack ingested cyanide capsules when they realized they were about to be captured.

With the death of Kim Il-sung, the regime in Pyongyang traded in overt acts of terrorism for the elegant simplicity of merely holding a gun to their adversary’s head. Granted, it was a particularly expensive gun, and one that required years of deft negotiating and boundless duplicity to secure, but the DPRK pulled it off. Westerners might be tempted to believe that North Korea has moderated its behavior since it has acquired a nuclear arsenal. Perhaps Pyongyang is content merely to threaten apocalyptic devastation in order to exact concessions rather than to send soldiers across the DMZ to plunge axes into the chests of American soldiers, as they did in 1976. That might be a misreading of North Korean tactics. The DPRK has always sought allowances from the West through terror, and its terrorism takes many forms.

After the North Korean’s tested a nuclear device in 2013, President Barack Obama declared the era of crisis-for-concession over. Since then, crises in the form of periodic naval incidents with Japanese and ROK vessels and provocative missile tests by Pyongyang have proliferated. On Tuesday, the North Koreans tested another nuclear device; one they dubiously contend was a hydrogen weapon. While the North Korean’s might not be capable of achieving thermonuclear detonation just yet, they have surprised international observers with their level of technological sophistication before. After a handful of failed attempts over the course of 2015, reports indicate that North Korea had successfully tested a nuclear-capable submarine-launched missile. In concert with the knowledge that the DPRK now has miniaturized nuclear weapons and could soon deploy them in SLBMs, North Korea is communicating that it has a second strike capability. If that is confirmed, the implications of such a realization are tremendous.

While North Korea may not have submarines capable of hauling a nuclear delivery vehicle to the West Coast of the United States just yet, they do have subs capable of making the trip. American experts who have so frequently underestimated Pyongyang’s technological prowess may not be able to soothe American tensions merely by noting that the DPRK is probably unable to park a nuclear weapon off the coast of San Francisco.  What North Korea can do, if not today in the very near future, is to deploy a miniaturized nuclear weapon atop an SLBM and put it within a few miles of Japanese or South Korean territory. If the West Coast is going to be increasingly nervous about the prospect of a North Korean submarine-launched nuclear delivery system, America’s East Asian allies will be panicked.

That’s the best-case scenario. In the worst case, North Korea has started a countdown clock. If the DPRK were to field an operational fleet of SLBMs that could carry either chemical or nuclear warheads (a threshold that is still months if not years away) that would render North Korea impervious to a preemptive strike aimed at disarming the rogue communist state. It would ensure that Pyongyang maintains a second strike capability that could not be preempted, and the Kim regime would know it. That would start the region’s Western allies thinking about their closing window of opportunity for preemption – as unpalatable as that might seem. The alternative is living with a rogue regime with a demonstrated penchant for terror that knows it can never be disarmed through force.

In the near term, the DPRK’s new nuclear test and its unnerving delivery systems will necessitate more Western sanctions, more targeting of North Korean money in Asian banks, and will put pressure on Seoul to accept Terminal High Altitude Area Defense (THAAD) missile defense batteries. In the interim, the allied nations in this region will have to be content to rely on American mutual defense commitments and the integrity of the U.S. nuclear umbrella. If Saudi Arabian, Egyptian, and Emirati behavior in recent years is any indication, the marginal utility of American security guarantees is starting to wear thin. North Korea never has to use a nuclear weapon to render American influence in East Asia muted and to strike terror into the hearts of U.S. allies and American citizens. The Hermit Kingdom is well on its way to achieving that goal.