But it took until this week for the North Korean leader to pick up the olive branch. In his New Year's Day speech, Kim Jong Un said he wanted to improve ties, "earnestly" wished the Olympics to be a success and suggested that representatives meet urgently to discuss his country's participation.
From there, events moved quickly.
Seoul responded with an offer of talks in the border village of Panmunjom. On Wednesday, North Korea opened a dormant cross-border hotline to facilitate communications. On Thursday, Washington and Seoul agreed not to hold military exercises until after the Games. On Friday morning, Seoul was able to announce that Pyongyang had formally agreed to the talks.
In Washington, President Trump and his administration signaled that they would not get in the way, with Trump even tweeting that talks are a "good thing."
John Delury, a professor of international relations at Yonsei University in Seoul, said that events had unfolded "seamlessly" this week, and that it is likely that the two sides will be able to reach an agreement on sending a North Korean delegation to the Olympics.
But beyond such sports diplomacy, officials and experts from Washington to Tokyo remain very wary.
They are suspicious of Kim's motives, noting that he vowed to spend this year mass-producing nuclear warheads and ballistic missiles. Kim also called on Seoul not to join Washington in "its reckless moves for a North-targeted nuclear war," and for it to discontinue joint military exercises with the United States.
There is, in other words, absolutely no sign that Kim has the remotest interest in turning his back on his nuclear program, and his agreement to engage in dialogue might simply be an effort to get relief from international sanctions, drive a wedge between Washington and Seoul and buy time to further develop his nuclear program.
"I think what is important is to maintain a firm defense posture," Japanese Defence Minister Itsunori Onodera told reporters in Tokyo on Friday, according to the Reuters news agency. "North Korea goes through phases of apparent dialogue and provocation, but either way, North Korea is continuing its nuclear and missile development. We have no intention of weakening our warning and surveillance."
Despite this caution, Trump and South Korea's Moon did agree to postpone their annual joint military exercises until after the Olympics, a gesture that should allow the Games to take place against a slightly less fraught backdrop.
Farther ahead, though, the dialogue process remains fragile and is likely to run into some very fundamental obstacles.
According to the White House, Trump and Moon agreed during a telephone conversation "to continue the campaign of maximum pressure against North Korea." But Kim surely will come into any dialogue process looking for financial rewards and relief from sanctions, experts say.
The idea of granting relief to Pyongyang will not go down at all well in Washington.
"There does seem to be evidence that the sanctions are beginning to really bite," said Paul Haenle, head of the Carnegie-Tsinghua Center in Beijing. With Kim feeling he may have achieved a "very minimal level of deterrence vis-à-vis the United States," he may now feel it is time for diplomacy.
"This also has the added benefit of driving a wedge between the United States, which is pressing hard for more and more pressure, and South Korea and China, whose preference is for finding a way to ratchet down tensions and shift to talks and diplomacy," he added.
In 2016, the Workers' Party of Korea held its Seventh National Congress, vowing to pursue nuclear weapons alongside economic development. On Monday, Kim declared the accomplishment of "the great, historic cause of perfecting the national nuclear forces" and stressed that his central aim this year is to improve people's standard of living.
"Once the nuclear weapon is completed, it's time to focus on economic development," said Chinese military commentator Song Xiaojun. "This needs a relatively peaceful environment. Moon Jae-in's administration is different from [previous president] Park Geun-hye's. There's an opportunity just in time — the Winter Olympics."
North Korea is skilled at exploiting differences in the international coalition calling for it to denuclearize. There is also the risk of the process falling apart when the joint exercises between the United States and South Korea do eventually take place after the Olympics, or if North Korea conducts another missile test, experts say.
"It's a good idea to talk to North Korea — it's the most dangerous country in the world, and we should always be ready to talk to them," said Robert Kelly, a professor of international relations at Pusan National University in South Korea. "But process is not a goal in itself."
Kelly warned that North Korea probably will treat its participation in the Olympics as a concession for which it will expect to be rewarded. "But these are not real concessions — they are costless," he said. "Who do you think is going to pay for North Korean athletes to come here? North Korea will treat this as a shakedown racket."
Liu Yang contributed to this report.