For South Koreans feeling the sentimental tug of One Korea — reveling in the possibility of a reunited national homeland — this past week has been exhilarating.
They've seen Olympic athletes from North and South share a flag and a hockey team. Pop idols have held hands with musicians from the North while singing "our hope is unification." And South Korean leaders have set aside monumental differences with their northern neighbours to exchange rare smiles and handshakes… and even consider a summit invitation to Pyongyang.
It's almost as if there were no longer a fear of a military attack by the other, no difference in worldview, no human rights abuses just north of the border.
"There are many reasons to not trust the North," said Kang Hyang-suk, a spectator who was recently watching the Games on a big TV at the main Seoul train station. "But if we can find ways to build trust together, I really believe something good will come out of it."
Indeed, the visit by Kim Yo-jong — the little sister of North Korean leader Kim Jong-un, and his personal peace envoy here — saw a whirlwind of southern hospitality.
She was treated to four banquets with senior officials, including a formal lunch with South Korean President Moon Jae-in in his official residence, the Blue House. Traditional delicacies from every part of Korea — North and South — were symbolically served.
There, Kim delivered a letter from her brother expressing a wish for peace and then, a verbal invitation to meet him in Pyongyang at President Moon's "earliest convenience." Moon made no promises, but through his spokesman, he said, "let's make the circumstances right for it to happen."
A lot hangs on that RSVP.
Broaching the nuclear issue
The invitation could be a ploy by the North, or a path to peace and maybe unification. It could divide the U.S.-South Korea alliance. It could diffuse the threat of nuclear war or, perhaps, deepen it.
So far, North Korea has refused to even discuss abandoning its nuclear weapons program, which Kim Jong-un has declared a success and ready for mass production of missiles.
Even supporters of Moon and his policy of conciliation with the North say that the weapons program is exactly what needs to be on the table now.
"We cannot go on forever avoiding the nuclear issue," said an editorial in Seoul's main left-leaning newspaper, Hankyoreh. It added that negotiations with the North are "going to have to afford some kind of starting point toward discussions between Pyongyang and Washington."
If the summit happens, it will be a very rare event. In his seven years in power, Kim Jong-un has never met a foreign leader. And there have been only two other inter-Korean meetings of this kind since the Second World War.
Determining an agenda
Few here think Moon will pass on this opportunity. He's been advocating such an approach his whole political career. Still, observers say he has to plan carefully.
"If Moon Jae-in is wise, he will insist that the nuclear issue is first on the agenda," said Lim Jae Chun, a professor of North Korean studies at Korea University. "Without it, I think South Korean public opinion will be very critical, and so will the U.S. and Japan."
U.S. Vice-President Mike Pence condemned the North's Olympic participation as he traveled to the opening ceremonies, and he maintained an icy distance from the Pyongyang delegation.
But on his trip home, Pence told the Washington Post he had agreed with President Moon on a way to coordinate U.S.-South Korean efforts.
Moon would tell the North it had to take concrete steps to abandon its nuclear program before sanctions would be eased. The U.S. would continue isolating the North until it complied.
"The point is, no pressure comes off until they are actually doing something that the alliance believes represents a meaningful step toward denuclearization," Pence said.
U.S. Secretary of State Rex Tillerson also said the U.S. is willing to have preliminary talks with North Korea to see if there is a foundation for serious negotiations.
The U.S. role
Is Pyongyang interested in talking to Washington?
In a recent statement, North Korea's state news agency, KCNA, continued a stream of insults that have been traded across the Pacific for months. The statement said U.S. President Trump "cannot deodorize the nasty smell from his dirty body woven with frauds, sexual abuses and all other crimes nor keep the U.S. from rushing to the final destruction."
But South Korean observers say the invitation is a clear sign the North is feeling pressure to change its bellicose approach. Economic sanctions, including severe restrictions on fuel imports, are biting. Plus, Washington has not ruled out a military strike of some kind.
"North Korea wants to have a dialogue with the United States, however, they don't know how to approach the U.S. directly," said Shin Chang-hoon, senior research fellow with the Korea Institute for Maritime Strategy. "They are testing this situation," he said, to see if South Korea could act as "a bridge."
He said North Korea "needs to get out of this dangerous situation, but needs to save face as well."
Still, there are strong feelings and loud voices in South Korea warning that this is all a ruse, that Kim Jong-un is playing for time while he finishes building nuclear missiles.
Protestors shadowed the North Korean delegation throughout its visit to the South, shouting insults and defacing posters of Kim.
Defectors from the North, like Choi Jung-hoon, are among Kim's fiercest critics. He used to be a political commissar in the North Korean military, keeping the troops loyal to the 'Supreme Leader," and said "South Korea is thoroughly being deceived by North Korea."
"Kim Jong-un wants to sit in the driver's seat of the Korean peninsula, and he's using the government here to get his way," Choi said.
Many in South Korea are skeptical — but the North's participation in the Olympics and its invitation for talks have made them just a little hopeful, too.