A worker in Hanoi places a flower into an arrangement displaying the North Korean flag ahead of the forthcoming summit between President Trump and North Korean leader Kim Jong Un. (Carl Court/Getty Images)

Expectations are low and fear is high regarding President Trump’s summit this week with North Korean leader Kim Jong Un. But despite all the hand-wringing, few have publicly discussed what a successful deal with North Korea might look like.

The United States’ interests are plain. It wants an end to the nuclear threat from North Korea, which at a minimum means the elimination of any missile capability to strike U.S. territory. Once that is achieved, it also wants a reduction in the North Korean threats to its South Korean and Japanese allies. The question, however, is how to translate those desires into a workable deal.

Nicholas Eberstadt, the Henry Wendt Chair in Political Economy at the American Enterprise Institute, has been studying the North Korean regime for decades. He is leery that Pyongyang would be willing to make a good deal for the United States, as it would represent a 180-degree turn for a regime that has starved its people to build a military clearly intended to conquer South Korea and, perhaps, even Japan. But on the off-chance that a leopard can change its spots, Eberstadt has identified four details that would indicate success.

The first is an accurate and full inventory of Pyongyang’s nuclear activities and infrastructure. “The North has never been willing to provide this,” Eberstadt said. “And why not? Once we know what they have and where they have it, we could strike to destroy it. Chairman Kim surely is afraid that we will do just that if given the chance.” Eberstadt’s point is well-taken. Nevertheless, unless we know what they have and where they have it, how can we know that we have accomplished the full denuclearization that Trump says he is aiming for?

The second follows from the first: on-site inspections by international experts, including challenge inspections. The latter point is key, as challenge inspections allow for the inspectors to go to any site they choose within a specified time period — including those that North Korea may not have identified, but which intelligence has discovered they are operating. Such inspections may not completely eradicate Pyongyang’s arsenal, but they surely would reduce it and hamper the ability to operate or expand it.

Recognition of South Korea’s legitimacy is the third hallmark of a good deal. It may surprise people to learn that North Korea still refuses to admit that South Korea is a free and independent state. “The North always tries to avoid such implicit grants of legitimacy,” Eberstadt said. “Any agreement Trump signs should both include references to South Korea and use the country’s legal name, the Republic of Korea, rather than the North’s preferred and ambiguous term, ‘south Korea.’ ” This seemingly minor point would send a message to our allies in Seoul that we are not cutting them loose to serve our own interests.

Eberstadt’s final point is purely political: North Korea should commit that its state-controlled media — print and electronic — communicate an uncensored message from Trump to the North Korean people. North Koreans have been told from birth that the United States is the enemy and that they are barred from listening to or reading material from the outside. Such a missive would be the first time many North Koreans would have direct contact with the free world, and a communication that expresses desires for peace and good relations could be the start of a slow opening of the North Korean mind.

Such a missive should also address the human rights abuses the North Korean regime perpetrates against its people. The North Koreans surely would not allow a direct assault on their government. On the other hand, clear, unambiguous statements about what normal life looks like in the United States and in South Korea would be a message to North Koreans that their lives can change dramatically for the better.

I doubt the president will get a deal in Hanoi that provides even one of these points. But he will be tempted to sign a deal anyway, fearful that failure of a second summit to produce a breakthrough will lead to loss of face and the belief that he is a failure.

President Ronald Reagan faced a similar choice in 1986. He met with Soviet General Secretary Mikhail Gorbachev in Reykjavik, Iceland, and the two leaders hastily negotiated an agreement that would dramatically reduce nuclear weapons. Reagan was enthralled, as such an agreement was a longtime goal of his. At the end, however, Gorbachev made a final demand: The United States had to abandon its research into anti-ballistic missile defenses, known as “Star Wars” if it wanted the agreement.

Reagan angrily refused. He knew the Soviets were engaged in similar research and he was not going to give away the United States’ potential ability to defend itself. Rather than take a bad deal, he walked away empty-handed. Less than a year later, the Soviets were back at the bargaining table, this time without the insistence that the United States give away the store.

Trump has negotiated hundreds of deals in his life and surely knows the old adage: “If you can’t walk away, you will overpay.” While he should hope for the best, he should be prepared for the worst. If he can’t get a deal along the lines Eberstadt laid out, he should emulate Reagan and just walk away.

Read more from Henry Olsen:

‘Vice’ isn’t the Best Picture of the year. The Academy would be crazy to vote for it.

Don’t fool yourself. The political center won’t recover anytime soon.

The fiscal nightmare in Illinois shows Democrats exactly what not to do

Alaska is set to be the next great reckoning for conservatives