There appears to be an air of optimism surrounding the summit between Donald Trump and Kim Jong Un, set to take place in just a few hours in Singapore. Discussions have progressed “more quickly than expected,” according to an official statement issued by the White House. North Korean state media have reported that in addition to the obvious discussions of denuclearization, Kim would focus on building U.S.-North Korea relations. Indeed, Western news agencies have speculated that the United States and North Korea have made so much progress that it is beginning to worry China, heretofore the designated middleman between the two sides.

The optimism is understandable. Yes, a meeting such as this is unprecedented, so it’s tempting to conclude that a major change is in the offing. But the optimism is a little premature. North Korea and the United States still view the world in fundamentally different terms. In fact, they can’t even agree on the definitions of the terms. To Washington, denuclearization requires incontrovertible proof that North Korea has destroyed its nuclear weapons program. To North Korea, denuclearization is something more akin to eliminating world hunger – a worthy goal to strive for but with little tangible implications in the short term.

With the imperatives of all sides in mind, there are three basic outcomes that could emerge from the summit. The first and most likely is a return to the status quo. It will be disguised by statements of victory, of course, and the “victory” will no doubt be captured for eternity by photographers and journalists. But in this version of events, neither side will be willing to blink, and little will change. North Korea will dangle concessions on its nuclear program in return for promises the United States cannot possibly keep, including withdrawing the U.S. military presence from South Korea. The United States will maintain a hard line on denuclearization and will offer some combination of security assurances and economic aid woefully inadequate for Kim to take home and save face. The two sides will recognize this politely and agree to hold more meetings, or they will recognize it impolitely and resume threatening each other.

The second potential outcome is that North Korea flips. China is North Korea’s traditional security patron. They signed a mutual defense treaty in 1961 that remains in effect today. North Korea may look across the Yalu River and see, not unreasonably, a potential long-term threat from China, a threat now punctuated by the elevation of Xi Jinping to Chinese dictator. After all, previous iterations of Chinese empires have occupied the Korean Peninsula throughout history. If Kim sees China, rather than the U.S., as the greater long-term threat to North Korean sovereignty, he may be willing to offer real concessions in return for an ironclad U.S. security guarantee. (It’s worth noting that Kim may rightly doubt the security guarantees of the U.S., which just withdrew from its most recent nuclear agreement with Iran.) This would put the U.S. in a difficult situation, dealing a blow to China but adding a weighty responsibility to Washington’s already full plate.

There is little evidence to support this otherwise rational line of thought. Kim has traveled to China twice in the past six months, and though bilateral ties were tense immediately after Kim’s rise to power, things have since normalized. By all accounts, Beijing and Pyongyang appear to be coordinating their moves. Of course, it’s possible that all this is misdirection on Kim’s part, a clever ploy meant to lull China into a false sense of complacency. But it’s highly unlikely. Since Trump enlisted China’s help on the North Korea issue just a few months after his inauguration, developments have generally proceeded in a way that have benefited China.

The third potential scenario is that the United States capitulates. In this scenario, Washington is willing to abandon its security commitments on the Korean Peninsula in return for a North Korean promise to denuclearize. At the broadest strategic level, this also makes some sense. After all, the U.S. became South Korea’s security patron in part because of a diplomatic oversight. Secretary of State Dean Acheson neglected to include South Korea in the United States’ defensive sphere in a major speech, which the Soviet Union viewed as de facto permission to rearrange the Korean Peninsula for its benefit. It was an understandable oversight; the containment strategy employed against the Soviet Union did not depend on South Korea. The containment line in the Pacific archipelago, ranging from the Strait of Malacca to Japan, was the most important element of U.S. strategy in the Pacific, and South Korea was irrelevant to it.

In other words, the U.S. was dragged onto the Asian mainland in Korea by accident, and the U.S. would be better served by reaching some kind of accommodation on Korea while improving relations with Japan, the Philippines, Taiwan and other Pacific nations in the archipelago. The problem here is that the U.S. has become so invested in South Korea that to withdraw from the peninsula now for the empty promises of a country as historically disingenuous as North Korea would be seen as a sign of tremendous weakness by U.S. allies – so much so that it might encourage them to find pragmatic accommodations with China or Japan if they think the U.S. is unable or unwilling to guarantee their security. These potential consequences make such a development extremely unlikely, no matter how much sense it makes in terms of the United States’ deployment of resources in Asia.

What is likely, of course, is defined by geopolitics, which over time tends to be as immutable as time itself. In the grand scheme of things, neither Trump nor Kim can change the basic variables of the situation. The U.S. needs to get North Korea to denuclearize, and North Korea needs to ensure regime survival. But history is rife with examples of individuals overcoming the constraints geopolitics places on them, and it’s possible that the Singapore summit will be another such example. Still, the fact is North Korea is probably too weak and the U.S. is probably too invested in South Korea for the issues that have confounded resolution to be resolved by this summit.