The historic reality show, featuring a cast of thousands (mostly journalists) is over, and the principals have returned home.

Kim Jong Un has seen first hand a large global city outside China, with Singapore providing an inspiring paradigm for what a non-nuclear Pyongyang might be some day.

Donald Trump has come to realize again that Asia is a more pleasant place for him to be than Europe, or even many parts of his own North American neighborhood, as the recent Quebec summit so clearly proved.

In the wake of the Singapore summit, how far have we moved along the road to a Korean peace? It is easy to be skeptical, but my take is that this recent summit was better held than not.

Maintaining close U.S.-Japan coordination in its aftermath will be a challenge, given some divergence in Japanese and Korean interests, combined with American sensitivity to both.

Yet all three countries share an interest in a prosperous Northeast Asia free of nuclear weapons, which far-sighted common policy must adopt as a transcendent goal.

In the wake of Donald Trump and Kim Jong Un's extended meeting, and the positive reaction to it that the two seemed to share, it is worth exploring, at least, whether North Korea is capable of seriously changing course.

Pyongyang has successfully tested both nuclear weapons and advanced missile systems, yet has not perfected them, giving it both the confidence and the incentive to talk.

And given its backward economy, together with tightened sanctions and an escalation of American threats over the past year, North Korea may also feel a greater need to negotiate than was previously true.

Personal relations can be an important dimension of foreign affairs, especially when nations lack mutual experience, interdependence, or reason to trust one another, as has been true for seven long decades between Washington and Pyongyang.

The United States may have lost some marginal leverage by agreeing uncritically to a summit that North Korea very much wanted. Yet Washington traded that leverage to open a promising short-term window for negotiation, and can always escalate pressure once again if those expectations are betrayed.

On what terms, then, might a bargain be had? Here it is important to remember the insights of Henry Kissinger. In his work on diplomatic history, Kissinger often contrasted the ironic failures of Europe's most brilliant conqueror, Napoleon Bonaparte, to the enduring successes of a much less well-known statesman, Austrian Foreign Minister Klemens von Metternich.

Napoleon made his name in history as an aggressive, self-righteous prophet -- the bearer of French revolutionary fervor, always righteous, who pressed his opponents to the limit, and never accepted less than victory.

In the end, however, as Kissinger's research showed, Napoleon's aggressiveness and unwillingness to compromise, however brilliant in tactical terms, led ultimately to his defeat -- both in the snows of Moscow, and ultimately on his final battlefield of Waterloo as well. That very refusal to compromise led his enemies to combine against him.

Metternich, by contrast, quietly placated his adversaries one by one, taking their values as given, and drawing them into a common, harmonious, and stability-oriented endeavor.

The system he created through consensus at the 1814 Congress of Vienna, known as the Concert of Europe, ended up enduring for fully a century -- five times as long as Napoleon's Continental System, and much less costly to maintain.

The historical insights of Kissinger are quite relevant to the problem of Korean peace today. It is crucial to ask -- far beyond the question of nuclear weapons or missiles, or even the process of their dismantling -- how to create a structure of peace which the key parties have mutual incentives to maintain.

For Japan and the United States, that structure no doubt includes CVID -- the complete, verifiable and irreversible denuclearization of North Korea -- and missiles that threaten both countries. A durable structure of peace must also include, on humanitarian grounds, the return of Japanese abductees. If those are the preconditions, however, what are the correlate concessions that would give Pyongyang a stake also in a stable peace?

Economic incentives would help, and financial affluence gives Japan some important leverage to ensure that its interests in a Northeast Asian peace are represented adequately. Most observers suppose that Japan would provide Pyongyang, in a final settlement, assistance equivalent to what was paid in 1965 to Seoul, in compensation for colonial rule, provided that the abductee and strategic issues are adequately addressed.

Yet incentives to agreement are not a matter of financial benefits alone. Incentives also must provide leverage, to assure that nominal agreements are enduring. The parties to an agreement, in a word, must have means of monitoring and enforcing it.


[Kevin Lim/THE STRAITS TIMES/Handout]

For North Korea to abandon its weapons and missiles, in short, it must be confident that it would retain other persuasive means of ensuring its security -- not just its prosperity. To create such incentives, it is thus important for negotiating partners to present a credible vision of how a non-nuclear North Korea could be secure.

That means, apart from a peace treaty, cross recognition, and security guarantees, finding credible non-nuclear, and ideally non-military leverage for all parties to an agreement.

A glance at the map shows us that North Korea stands between South Korea and the Asian continent, dominated by China and Russia. Developing North Korea's transit role between South Korea and Eurasia as a whole -- especially transit for energy -- would be a useful way of giving it constructive leverage.

One concrete possibility could be natural gas pipelines or electric power grids, from Russia or China, across North Korea, into Seoul. Transportation routes from the South across North Korea to Pyongyang's northern neighbors could play an analogous role, as could large hydro-electric projects.

These public works could provide Pyongyang with income, and simultaneous leverage to enforce broader regional agreements regarding its denuclearization.

Many of them could be financed by Japan or the financial institutions in which Japan has a major say, such as the Asian Development Bank or the World Bank.

Such projects should be considered seriously, following North Korea's CVID, as a Kissingerian means of creating an enduring structure of peace in Northeast Asia.

(Kent E. Calder is director of the Reischauer Center for East Asian Studies at SAIS/Johns Hopkins University in Washington.)