THESE ARE nauseating times to be a leader. Above, the sky is a mass of storm-clouds and swirling portents of change.

Below, the earth itself feels treacherous. Small wonder that those who run the world, whether in politics or business, long to stand on more solid ground.

That is why, when they gather, they talk of de-risking and hedging, and of ways to rely less on partners who have forfeited their trust.Yet President Donald Trump breaks new ground by treating inconstancy as his superpower. This is true in foreign policy, as he threatens to bomb countries before offering them friendship in the next breath. (REUTERS FILE)Alas, many attempts to find a firmer footing are doomed.

In part, that is because an array of uncontrollable forces—whether economic, technological, ideological or demographic—really are reshaping the world in dramatic ways. But it is also because powerful or unusually ruthless actors are doing their best to keep the world off-balance.Uncertainty is increasingly being used as a weapon.

The list of countries behaving unpredictably to gain an advantage begins with America and China. Not long ago, those two giants saw an interest in upholding a stable and predictable global trading order (while bending its rules as needed).

Now the two countries both see an interest in ambiguous rules and hard-to-enforce agreements that leave trade partners dependent on their goodwill.To be sure, statesmen have been masters of ambiguity since they wore robes and swords, and carved treaties on stone tablets. In the modern era, what is more, America has always been careful to avoid offering hard-and-fast security guarantees to allies, lest they were to start foolish conflicts, believing that Uncle Sam would come to their aid.Yet President Donald Trump breaks new ground by treating inconstancy as his superpower.

This is true in foreign policy, as he threatens to bomb countries before offering them friendship in the next breath. It is the case in trade policy, as he adjusts tariff rates and export controls on a whim.

When Trump aides are asked how foreign governments or investors are supposed to take long-term, multi-billion dollar decisions if the terms of a deal may later change, they serenely reply that “there is a value to uncertainty”. In their telling, unease usefully reminds foreigners that access to America’s market is a privilege, not a right.

They note the advice of the president himself: if outsiders wish to avoid tariffs, all they need to do is to make things in America.In Trumpworld, American dominance is enhanced when foreigners do not know where they stand. In the context of the Ukraine war, that might involve Europeans pleading for continued access to American-made weapons or the Starlink satellite-internet system owned by Elon Musk.

In future, it might involve access to the best AI models. Foreign pleading is the win.China has spent decades tut-tutting at America’s high-handed and changeable ways.

For years, officials in Beijing would accuse America of nagging trade partners to open their markets, only to turn around and enact export controls and other curbs before a foreign rival became too formidable a competitor. America changes the rules when it fears losing a game, they would grumble.

Worse, America claims to enjoy a “long-arm jurisdiction” to enforce its laws worldwide, Chinese legal experts complained.The grumbling lasted until China became dominant in the production of vital industrial inputs and technologies, from rare-earth elements to batteries. Just in time for Mr Trump’s uninhibited second turn at the presidency, China found itself in a position to retaliate in relative safety, as its longstanding quest to achieve self-reliance in critical technologies at last paid off.

In the past couple of years China has enacted its own export controls and long-arm laws to punish foreign companies if they obey American laws and sanctions that hurt China.If a multinational firm is now paralysed with doubt, not knowing how to balance laws in America, where it is listed, with those in China, where it sources important components, that is not an accident. In an echo of Mr Trump’s line—to avoid tariffs, make things in America—China has its own blackmail to propose.

If companies wish to avoid the vaguely-written, politicised rules that govern export licences for rare earths and the like, they can make products in China and export them as finished batteries or electric cars. The offer is not subtle: China-based factories have no trouble sourcing rare earths; dependency is a small price to pay.If carrots do not work, China has sticks to use on foreigners trying to de-risk and diversify away from dependency on its supply chains.

Specific rules aim to stop foreigners building up stockpiles of critical minerals, and even govern the export of machines to process and recycle them. Some Chinese controls are currently suspended as trade talks continue with America and Europe, yet hang like a sword over negotiators.Russia’s goal: make enemies doubt truth itselfNor are great powers alone in stoking uncertainty.

With global nerves a-jangle, such longstanding rogues as Russia see chances to frighten and befuddle foreign adversaries. European governments cannot be sure whether recent bomb threats that grounded flights were hoaxes and part of Russia’s hybrid war against NATO, or a precursor to actual attacks.

They are meant to be unsure.Iran, another lover of ambiguity, is also taking advantage of a world on edge. With the war in the Gulf stalemated, Iran stands accused of mounting hard-to-attribute attacks across the West.

On November 9th France blamed Iran’s Revolutionary Guard Corps for cyber-attacks that remotely turned freezers into ovens in European supermarkets, starting several fires. (Traces of Persian in the attackers’ computer code were a clue.) What logic guides Iranian hackers to spoil food in a Belgian supermarket? Queasy Western leaders know the answer.

Logic has nothing to do with it. In brutal times, doubt is the win.