A new North Korean law calls for "automatic" nuclear launches if the country's leadership or command and control systems are threatened, underscoring leader Kim Jong Un's fears of a so-called "decapitation" strike, experts said.
In an updated nuclear policy law passed on Thursday, North Korea enshrined the right to use preemptive nuclear strikes to protect itself, with Kim saying the legislation makes the country's nuclear status "irreversible" and bars denuclearisation talks.
The law outlines when North Korea could use its nuclear weapons, including if there is an attack on the government's leadership or the nuclear command and control system.
"In case the command and control system over the state nuclear forces is placed in danger owing to an attack by hostile forces, a nuclear strike shall be launched automatically and immediately to destroy the hostile forces," the law states, according to state news agency KCNA.
Kim has "monolithic command" over the nuclear forces, but the law's wording may indicate that if he is killed, a senior official would be designated to authorize nuclear strikes, said Ankit Panda of the US-based Carnegie Endowment for International Peace.
"The basic idea here is to communicate to the United States and South Korea that decapitating the North Korean leadership would not spare them nuclear retaliation," he said, noting that there are precedents in other nuclear states, including the United States during the Cold War.
Both the United States and Russia have employed technical systems, including the Soviet Union's infamous "Dead Hand," designed to ensure nuclear retaliation even if leaders are killed.
For now, that sort of "fail deadly" system in North Korea seems unlikely, Panda said.
"I would expect, for the moment, the fail deadly system would rely on organizational steps: for instance, the First Secretary of the Workers’ Party could confirm that Kim Jong Un had been killed in the course of a conflict, thereby authorizing the release of nuclear weapons," he said.
Although South Korea and the United States say they do not seek to change North Korea's government by force, both countries have war plans that imply strikes against Pyongyang's leadership.
Amid the "fire and fury" tensions of 2017 the Trump administration insisted it had no intention of launching a "bloody nose strike" against Kim, but had privately reviewed and updated war plans for a decapitation strike, according to a book by journalist Bob Woodward.
South Korean President Yoon Suk-yeol, who took office in May, has publicly given new emphasis to the so-called "Kill Chain" system to counter a North Korean nuclear attack, and is pouring resources into boosting the weapons that would be used under such plans, including F-35A stealth fighters and missiles launched from submarines.
First developed a decade ago as North Korea ramped up its nuclear development, Kill Chain calls for preemptive strikes against the North's missiles and possibly its senior leadership if an attack appears imminent.
In his speech discussing the new law on Thursday, Kim cited Kill Chain and its related strategies by name, saying they justify North Korea's nuclear development.
"This would seemingly warn away any notions of 'bloody nose' strikes, assuming any administration contemplates that again," Rob York, director for regional affairs at the Hawaii-based Pacific Forum, said of the new law.