The Pentagon's announcement that the United States will modernise its nuclear arsenal, introducing two new "low-yield" submarine-launched nuclear missiles, and resume large-scale bilateral military exercises with South Korea "immediately after" the Paralympic Winter Olympics indicate that tensions will soon rise again on the Korean peninsula.
At this stage, the Games seem likely to be free of major security incidents, but security officials in the South are planning for a range of domestic contingencies.
The Games will take place from February 9 to 25 in Pyeongchang County in the South. This will be the country's second Olympics and its first Winter Games. (Seoul hosted the Summer Games in 1988.) Ninety-two nations will take part, with 2925 athletes in 102 events. The Paralympic Games will be held in the same place from March 9 to 18, with more than 550 athletes in 80 events.
Australia has 51 athletes competing in Olympic events and 10 to 12 in the Paralympics.
North Korea will have 22 athletes competing in the Winter Games; the South 146. All will enter the opening ceremony marching under the Korean unification flag. There will also be a united Korean team in women's ice hockey.
The North will try to offset the athlete imbalance with its "army of beauties": a 230-member all-female cheer squad. (Prerequisites for selection were to be young, over 160 centimetres tall, physically attractive and well-coordinated, university-qualified and with no relatives outside North Korea.)
National security continues to be a sensitive issue in the South amid last year's tensions over the North's nuclear tests and missile launches – suspended in November 2017 to allow face-to-face talks to take place between the two countries. It seems very unlikely the North would want to disrupt the Games when it is sending a large delegation to Pyeongchang and its athletes are taking part.
Even so, the Department of Foreign Affairs and Trade recommends that Australians monitor developments closely, because tensions on the peninsula can escalate with little warning. The South has released a free smartphone app, Emergency Ready App, which has information on local services (police, fire and ambulance), hospitals and emergency shelters.
Before and during the Games, security is likely to be tight at points-of-entry into the South and, of course, at all the Games venues. Security officials will also be prepared for a variety of potential domestic challenges.
First will be incidents intended to embarrass and undermine the South Korean government. These could include left-wing, anti-US and anti-corruption demonstrations.
Second, a terrorist attack on a national team that is a desirable target – particularly the US team because of the US's leadership against Islamist extremism.
Third, others who could pose security problems, such as anarchists and mentally ill people.
To protect athletes, most national teams will have accompanying security officers. The US always has a large security group accompanying Olympic athletes and, for the past several Winter Games, has housed its team in a secure compound away from other athletes. The Israeli, British, French and German teams are also likely to have their own protection.
Another security issue will be crime against visitors. DFAT notes that the crime rate in the South is usually low, but petty crime exists in major cities. There have also been sexual assaults and other violent crimes against foreign tourists and expatriates, sometimes following drink-spiking.
Non-violent criminal activity always follows the Olympics, such as ticket fraud, attempts to fix events, counterfeiting of Olympic collectables, pickpocketing, opportunity theft, selling of narcotics and so on.
Visitors are advised to care for their belongings when in crowded places; not to accept drinks, food, gum or cigarettes from strangers or new acquaintances; not to leave food or drinks unattended; to exercise care when walking alone at night; and to avoid using unofficial taxis.
Looking at the post-Olympics period, North Korean's main ongoing security concern will be a US military attack to destroy the North Korea. It is particularly concerned that large-scale South/US military exercises are preparations for an invasion, especially when they involve beach landings.
The US/South Korean military exercises, code-named Key Resolve and Foal Eagle, take place each year in March and April, involving about 30,000 personnel. US President Donald Trump agreed to defer the current exercises until after the Games.
The North believes the only way to safeguard Kim Jong-un's regime and prevent the US attacking is having a nuclear deterrent, with nuclear warhead-equipped missiles able to reach US territory.
The new Olympic atmosphere of harmony on the peninsula seems unlikely to last. "Normal" tensions will probably resume with the next round of South Korean/US military exercises. The North has already warned it will not "sit idle" if these exercises resume.
Being experts in unpredictability themselves, North Koreans continue to worry that volatile Trump will one day attack the North to divert Americans' attention from his problems at home.