(CNN) North Korean leader Kim Jong Un heads into 2017 with two things that loom ominous for the rest of the world -- he's tested a nuclear weapon, and no one really knows how willing he'd be to use one in anger.
North Korea conducted two nuclear tests in 2016, one in January and another, its most powerful ever, in September. Add that to a string of missile tests, both land- and sea-launched, and the world has plenty of reason for worry.
"Combining nuclear warheads with ballistic missile technology in the hands of a volatile leader like Kim Jong Un is a recipe for disaster," Adm. Harry Harris, the head of the US military's Pacific Command, said in a December speech.
Bruce Bennett, senior defense analyst at the Rand Corporation think tank, went further still, saying Kim "might be considered the world's most dangerous man."
But just how much of a threat does North Korea pose?
Pyongyang's September test put North Korea's nuclear program in its strongest position ever, at least according to the Kim regime, which claimed to have successfully detonated a nuclear warhead that could be mounted on ballistic rockets.
North Korean state media said the test would enable North Korea to produce "a variety of smaller, lighter and diversified nuclear warheads of higher strike power." Western experts fear that could expand the range of North Korea's nuclear weapons, possibly putting Alaska, Hawaii or even the US mainland in danger.
The warhead tested in September was estimated to have a 10-kiloton explosive power, almost twice as large as the one tested in January, said Kim Nam-wook of South Korea's Meteorological Administration. The atomic bomb dropped by the US on Hiroshima in 1945 is estimated at 15 kilotons.
Despite Pyongyang's apparent progress on a warhead, Bennett, the Rand analyst, points out that North Korea's test of its delivery systems, those missiles and rockets, weren't promising enough to make it a global threat -- at least not yet.
"To be such, the North would need to have developed some form of reliable delivery mechanism for its nuclear weapons that could reach anywhere in the world. And the North has not yet done that," Bennett said, pointing out that of the eight tests of longer range missiles (2,000 miles or more), seven were considered failures, and the other was tested only over a short range.
And despite testing a submarine-launched missile in August, the North has only one submarine capable of launching such a missile -- and its range is short, making it unlikely to get past Western defenses to pose a threat beyond Asia, added Bennett.
Doubts about its delivery capabilities notwithstanding, North Korea remains the only country on Earth to test a nuclear weapon in the 21st century -- and that offers Kim considerable leverage, analysts say, especially with his continued ability to tolerate the West's only real weapon short of military action, economic sanctions.
"The sanctions would undoubtedly deter North Korea's economy and make the country further isolated ... but Kim Jong Un and his associates believe it is still worth it for them to have an advanced nuclear capability," said Seung-Kyun Ko, a professor at Hawaii Pacific University and a former research commissioner in South Korea's Ministry of Foreign Affairs.
Nuclear weapons are "a tool for giving the oppressed people pride and hope," Ko said.
The voraciousness of Kim's "nukes at all costs" philosophy was hammered home just this week when a high-ranking North Korean diplomat who defected to the South earlier this year said Kim wouldn't back down even if offered huge sums of money by Western powers.
Thae Yong-ho, formerly No. 2 at the North Korean Embassy in London, said Kim is "racing ahead with nuclear development after setting up a plan to develop nuclear weapons at all costs by the end of 2017."
The suggestion that Kim can't be bought off is echoed by Boris Toucas, a visiting fellow at the Center for Strategic and International Studies in Washington.
"Kim Jong Un has made the development of the nuclear program its main source of legitimacy, connecting his fate to what he sees as the greatness of his nation, well before economic progress," Toucas wrote in October, shortly after Pyongyang's second nuclear test of 2016.
Analysts agree that Kim is far from the unstable madman many present him to be. In fact, Ko, the former South Korean Foreign Ministry official, called the North Korean leader "cautious and calculating."
For instance, Ko said, Kim knows he can use the annual string of US-South Korean military exercises, involving thousands of troops and the latest US weaponry, to his advantage.
"He demands from his people and subordinates complete obedience to his leadership, because the country is on the verge of imminent invasion from the US and South Korea," Ko said. "He creates cohesion and unity among his people in facing the invasion."
While he keeps his people in line with talks of an impending invasion, he keeps his adversaries off balance by talking peace.
"Kim continues to pursue a peace treaty with United States," explained Bennett, the RAND expert. "And if he succeeds in getting such a treaty, it is entirely possible that US forces would be withdrawn from South Korea within a few years, likely to never return."
In other words, Kim wins if US troops get off his doorstep.
Thae, the defected diplomat from the North, said this week that Kim senses weakness in the US and South Korea right now.
"Due to domestic political procedures, North Korea calculates that South Korea and the US will not be able to take physical or military actions to deter North Korea's nuclear development," the defector said at a news briefing in Seoul.
Those "domestic political procedures" include the impeachment case against South Korea President Park Geun-hye over a corruption scandal and the upcoming inauguration of Donald Trump as US President.
But Trump could be a wild card, perhaps as spontaneous as Kim is calculating.
Take Trump's comments on Taiwan and the South China Sea, for example. They might be helping mend the strained but traditional alliance between North Korea and China.
"While most observers argue that North Korea successfully exploits the distrust between China and the United States, they often overlook the fact that distrust between North Korea and China has grown at an even greater pace over the past few years, with North Korea constantly embarrassing its neighbor," Toucas, a former official in the French Foreign Ministry, wrote in October, reiterating that any Western deal with North Korea would need Beijing on board.
It's the kind of thing that could leave Kim wondering just what he is facing with the incoming leader of the free world.
"I think Kim Jong Un doesn't know how to size up this person, and vice versa," said Jasper Kim, a professor at of Ewha Women's University in Seoul. "It's an interesting tale of two alpha males and how they're sniffing each other out at this point."
The beginning of the year, at least, could be quiet.
"I heard from a North Korean official that they do not want to make any provocative actions until they know what kind of North Korean policies are in the next administration," said Park Hwee-Rhak, of Kookmin University in Seoul.
That means the initiative may be Trump's. He's said he would consider pulling US troops from South Korea. He's even said he might be willing to meet the North Korean leader for discussions over a hamburger, something that would please Kim, who "craves recognition as much as he does nuclear weapons," according to Toucas.
But Trump has also called Kim "a maniac" who needs to be dealt with harshly -- a course of action Park thinks Trump should take.
"I think Mr. Trump should play hard ball. I think he should ask for a review and consideration of the military options, including pre-emptive strikes," Park said.
But if Kim thinks that's in the works, Ko said the North Korean leader could strike out fiercely.
"He tends to be blunt and a bit extreme in his responses to his perceived threats."