South Korean President Lee Jae-myung’s choice of Tokyo and not Washington for his first state visit since coming to power was no accident.

It was a calculated and headline-grabbing signal that the tectonics of East Asia might now be shifting. On August 23, the two leaders staged a rare get-together between Seoul and Tokyo despite being neighbours long connected by suspicion as much as by geography.

Korea’s Lee once branded Japan “an enemy country.” Now, he talks of “mutually beneficial cooperation.” For his part, Prime Minister Shigeru Ishiba opted for a word rarely used in Japan’s official vocabulary when referring to past actions on the Asian mainland: “remorse”. It was a cautious but measured olive branch offered by the Japanese PM.

But strip away the diplomatic choreography, and the stakes become much clearer. This was not just a get together meant to discuss business opportunities or even the improving of relations. It was a bilateral meeting focussed on survival in a region under mounting strain. Advances in AI, massive leaps forward in the use of clean energy, nuclear power included, and cross-cultural exchanges combined to offer the national dailies in both countries more than a few articles in the days following Lee’s arrival in Tokyo.

The real reason for the coming together of two long-time rivals, if not out-and-out enemies, however, was trilateral security coordination with Washington. Without it, both governments risk being outmanoeuvred by an ever erratic America with President Donald Trump at the helm, and an increasingly aggressive China.

Ghosts that refuse to die

For all the smiles and handshakes though, history hovers over every word. Lee’s promise to respect past agreements on forced labour and “comfort women” goes further than many in Seoul expected – and it annoyed many. Ishiba’s language meanwhile was welcome, but it was also modest and gave little away.

This was perhaps most evident over the issue of the Takeshima islets, also known as Dokdo in South Korea – a collection of rocks in the Sea of Japan (East Sea in Korea) that fuel nationalist passions on both sides. The dispute was not mentioned. Not once. In essence ignored, this time, the issue will not go away, however, and anyone who thinks those islands will stay out of future discussions between Japan and South Korea needs a rethink.

Trade wars and Trump

The economic front is no less combustible. Donald Trump’s return to the political stage looms large over both nations and in essence casts a shadow over every East Asian bilateral relationship. Trump’s “America First” playbook makes Tokyo and Seoul uneasy bedfellows as neither wants to be caught out of step with Washington, yet both fear historical issues being used to play each off against the other – a methodology Trump is becoming more and more capable of.

Perhaps in part because of this, at the summit, Ishiba and Lee pledged an ongoing cycle of security and economic cooperation with the US. But markets at home and abroad will be looking for substance: joint infrastructure projects, supply chain coordination and most of all trade liberalisation. Without these, talk remains just that - talk.

And in northeast Asia, history has a nasty but ever so repetitive way of barging back in whenever politics turns sour.

In that regard, the most immediate threats to this diplomatic reset right now are not in Pyongyang or Beijing though, but in Tokyo and Seoul themselves. Ishiba is fighting for his political life. The Liberal Democratic Party’s loss of its bicameral majority has given hardliners inside and outside the party new leverage. These are the types who do a double-take if they hear the word ‘remorse’ and for decades have served as kingmakers in the LDP.

In South Korea meanwhile, Lee is struggling to keep his approval ratings afloat just months into his presidency as he finds himself battered by domestic scandal and populist pressure, and for both men, as has been seen many times in recent years, stoking nationalist resentment remains a ready-made escape route if cornered at home.

Thus the paradox - both leaders need the reset to succeed abroad, but either could be forced to sabotage it for survival at home. The ghosts of history are not just diplomatic irritants, they are political lifelines.