THE YEAR 2025 is really like any other, only more so: It deserves to be greeted with what one of my former editors calls “paranoid optimism.”

Optimism is in order because the world, chaotic as it currently looks, might get better — and, yes, in part because a new American president, Donald Trump, could tackle problems in such mind-bogglingly unorthodox ways that breakthroughs become conceivable. The paranoia is called for because the world is complicated, with dangerous feedback loops hidden inside today’s “polycrisis.” And a leader as proudly unpredictable as Trump might inadvertently blow it all up.

We’ll have to get used to this ambiguity, which evokes the famous cat in Erwin Schrodinger’s thought experiment (about quantum superposition, if that means something to you). The poor creature sits in a sealed box and is simultaneously alive and dead; but only until you open the box and look. Thereafter it’s either one or the other. Something similar will happen once Trump takes his oath of office and starts owning every mess in the world.

Here are just a few examples in international relations that illustrate how various cats could live or die. They derive from the most important bilateral relationship in the world, the one between the United States and China. If and when these two cooperate, almost any problem becomes solvable. When they don’t, every pickle has the potential to escalate to Armageddon.

You may not have noticed this in your social-media stream, for instance, but since 2021 the leading killer of Americans between the ages of 18 and 45 has been fentanyl, or some other synthetic opioid based on it. One reason (of several) is that China, sulking over US support for Taiwan and other perceived snubs, turned a blind eye to the illegal production of the requisite chemicals by Chinese triads; those molecules then made their way to Mexico, where drug cartels packaged them for sale in the US. When Sino-American relations are bad, people die.

A bit over a year ago, though, Joe Biden and Xi Jinping met and agreed to pull back from the brink. China now cracks down harder on the triads (although plenty of the drugs still make it out). And lo, fentanyl deaths started declining in 2023 and are now plummeting. (Again, the reasons are complex, but this is one.) When Washington and Beijing cooperate, people live.

Now apply this to other cats trapped in boxes over which Xi and Trump will soon have joint custody. One is the prospect of nuclear war, or of an arms race that could lead to it. This year, China added another 100 atomic warheads to its arsenal, for a total of about 600; it plans to catch up with the US and Russia in about a decade. (Each of those has deployed about 1,700 nukes for instant use, with thousands more in storage.) Will all three keep arming, in a vain effort to outdo the others? In time, this could lead to feline mass extinction.

If, however, Trump and Xi agree to put brakes on this insanity, as Ronald Reagan and Mikhail Gorbachev once did, there is hope. Together, they could persuade Russia’s Vladimir Putin, and possibly even North Korea’s Kim Jong Un and the mullahs in Iran, to participate in arms-control talks. Xi has the requisite sway with them; and Trump — according to, well, Trump — is a negotiating genius.

Xi’s clout in Moscow, Pyongyang, and Tehran is also a segue to a parallel threat to world peace, the formation of a new “axis” among these regimes (akin to that other one between Nazi Germany, Fascist Italy, and Imperial Japan). Step by step, these four autocracies are moving from informal cooperation in undermining the US and the “order” for which it stands to formalized ties: Under this year’s pact between Russia and North Korea, for example, North Korean troops are now fighting and dying alongside Russian soldiers in Putin’s war against Ukraine.

This de facto axis will put the Trump administration in a bind. So far Washington, under Democratic and Republican administrations, has viewed conflicts in Ukraine, the Middle East, the Korean peninsula, the Taiwan Strait and South China Sea as discrete. If there’s even a hint that the four adversaries might coordinate their plans of attack — or barring that, recalculate opportunistically and strike when they believe that the US is distracted — the risk rises that the “theaters” become linked. The US military is currently set up to win one major war and one minor war simultaneously; if it had to confront the entire axis, it would have to wage four and might lose.

The proper label for that scenario is World War III. It’s a term that Trump has used often and that clearly haunts him. Instead of offering a strategy to prevent this nightmare, he has so far only touted his own alleged “strength,” whatever that means. To translate this bumper sticker into military might, he’d have to double or triple America’s defense budget, which would cause a fiscal and political crisis.

So his only practical option is to break up the axis before it becomes real. That again means he must talk to Beijing, which deems itself the hub of any emerging anti-Western alliance even as it looks askance at Moscow and Pyongyang getting too cuddly. If Trump and Xi talk, people will live; if not, people may die.

So it goes for almost every major problem. The United Nations, for example, has gone from merely dysfunctional to essentially irrelevant. One reason: Three of the five permanent (and veto-wielding) members of the security council keep sabotaging one another and the whole system. The US vetoes resolutions pertaining to Israel, while China and Russia protect each other, as well as North Korea and other rogues. (By contrast, the other two permanent members, Britain and France, have admirably refrained from using their vetoes for more than three decades.) If Trump and Xi wanted to resurrect the international system (which Trump admittedly claims to disdain), they could jointly declare a moratorium on vetoes.

The best example, of course, is climate change. I hesitate to bring it up because it’s hardly top of Trump’s mind, or even tucked away in any nook of it. But that could change, especially if he’s reminded that he should leave a positive legacy. Historically, the US has been the largest emitter of carbon into the atmosphere, although China has taken the top spot since 2005. If these two countries cooperate to slow global warming, there’s hope; if they don’t, there isn’t.

This is where paranoia bubbles up from my amygdala. As of now, Trump shows little interest in any of these sweeping thoughts and ambitions. He instead appears focused on starting a trade war with China, and then the whole world, because “the most beautiful word in the dictionary is ‘tariff’.” That’s a bad idea economically, and astoundingly petty. It’s also the worst possible way to start off with Xi. And remember: If they don’t get it together, cats will start dying.

Then the optimism fights back. It’s Trump’s shtick to trash-talk his interlocutors, friend or foe alike, just to see how they’ll react. But he also knows — at least I hope he does — that solving problems in the real world, whether in Ukraine, at the southern border, or anywhere else, requires finesse and an open mind. And neither he nor Xi (no pun intended) wants to blow up the world. Onward then, and welcome, 2025.

BLOOMBERG OPINION