Asked last month whether he was planning to join Israel in attacking Iran, US President Donald Trump said “I may do it. I may not do it. Nobody knows what I’m going to do”.
He let the world believe he had agreed a two-week pause to allow Iran to resume negotiations. And then he bombed anyway.
A pattern is emerging: The most predictable thing about Trump is his unpredictability. He changes his mind. He contradicts himself. He is inconsistent.
“[Trump] has put together a highly centralised policy-making operation, arguably the most centralised, at least in the area of foreign policy, since Richard Nixon,” says Peter Trubowitz, professor of international relations at the London School of Economics.
“And that makes policy decisions more dependent on Trump’s character, his preferences, his temperament.”
Trump has put this to political use; he has made his own unpredictability a key strategic and political asset. He has elevated unpredictability to the status of a doctrine. And now the personality trait he brought to the White House is driving foreign and security policy.
It is changing the shape of the world.
Political scientists call this the Madman Theory, in which a world leader seeks to persuade his adversary that he is temperamentally capable of anything, to extract concessions. Used successfully it can be a form of coercion and Trump believes it is paying dividends, getting the US’s allies where he wants them.
But is it an approach that can work against enemies? And could its flaw be that rather than being a sleight of hand designed to fool adversaries, it is in fact based on well established and clearly documented character traits, with the effect that his behaviour becomes easier to predict?
Attacks, insults and embraces
Trump began his second presidency by embracing Russian President Vladimir Putin and attacking America’s allies. He insulted Canada by saying it should become the 51st state of the US.
He said he was prepared to consider using military force to annex Greenland, an autonomous territory of America’s ally Denmark. And he said the US should retake ownership and control of the Panama Canal.
Article 5 of the Nato charter commits each member to come to the defence of all others. Trump threw America’s commitment to that into doubt. “I think Article 5 is on life support” declared Ben Wallace, Britain’s former defence secretary.
Conservative Attorney General Dominic Grieve said: “For now the trans-Atlantic alliance is over.”
A series of leaked text messages revealed the culture of contempt in Trump’s White House for European allies. “I fully share your loathing of European freeloaders,” US Defence Secretary Pete Hegseth told his colleagues, adding “PATHETIC”.
In Munich earlier this year, Trump’s Vice-President JD Vance said the US would no longer be the guarantor of European security.
That appeared to turn the page on 80 years of trans-Atlantic solidarity. “What Trump has done is raise serious doubts and questions about the credibility of America’s international commitments,” says Prof Trubowitz.
“Whatever understanding those countries [in Europe] have with the United States, on security, on economic or other matters, they’re now subject to negotiation at a moment’s notice.
“My sense is that most people in Trump’s orbit think that unpredictability is a good thing, because it allows Donald Trump to leverage America’s clout for maximum gain…
“This is one of his takeaways from negotiating in the world of real estate.”
Trump’s approach paid dividends. Only four months ago, Sir Keir Starmer told the House of Commons that Britain would increase defence and security spending from 2.3% of GDP to 2.5%.
Last month, at a Nato summit, that had increased to 5%, a huge increase, now matched by every other member of the Alliance.
The predictability of unpredictability
Trump is not the first American president to deploy an Unpredictability Doctrine. In 1968, when US President Richard Nixon was trying to end the war in Vietnam, he found the North Vietnamese enemy intractable.
“At one point Nixon said to his National Security Adviser Henry Kissinger, ‘you ought to tell the North Vietnamese negotiators that Nixon’s crazy and you don’t know what he’s going to do, so you better come to an agreement before things get really crazy’,” says Michael Desch, professor of international relations at Notre Dame University. “That’s the madman theory.”
Julie Norman, professor of politics at University College London, agrees that there is now an Unpredictability Doctrine.
“It’s very hard to know what’s coming from day to day,” she argues. “And that has always been Trump’s approach.”
Trump successfully harnessed his reputation for volatility to change the trans-Atlantic defence relationship. And apparently to keep Trump on side, some European leaders have flattered and fawned.
Last month’s Nato summit in The Hague was an exercise in obsequious courtship. Nato Secretary General Mark Rutte had earlier sent President Trump (or “Dear Donald”) a text message, which Trump leaked.
“Congratulations and thank you for your decisive action in Iran, it was truly extraordinary,” he wrote.
On the forthcoming announcement that all Nato members had agreed to increase defence spending to 5% of GDP, he continued: “You will achieve something NO president in decades could get done.”
Anthony Scaramucci, who previously served as Trump’s communications director in his first term, said: “Mr Rutte, he’s trying to embarrass you, sir. He’s literally sitting on Air Force One laughing at you.”
And this may prove to be the weakness at the heart of Trump’s Unpredictability Doctrine: their actions may be based on the idea that Trump craves adulation. Or that he seeks short-term wins, favouring them over long and complicated processes.
If that is the case and their assumption is correct, then it limits Trump’s ability to perform sleights of hand to fool adversaries – rather, he has well established and clearly documented character traits that they have become aware of.
The adversaries impervious to charm and threats
Then there is the question of whether an Unpredictability Doctrine or the Madman Theory can work on adversaries.
Ukrainian President Volodymyr Zelensky, an ally who was given a dressing down by Trump and Vance in the Oval Office, later agreed to grant the US lucrative rights to exploit Ukrainian mineral resources.
Vladimir Putin, on the other hand, apparently remains impervious to Trump’s charms and threats alike. On Thursday, following a telephone call, Trump said he was “disappointed” that Putin was not ready to end the war against Ukraine.
And Iran? Trump promised his base that he would end American involvement in Middle Eastern “forever wars”. His decision to strike Iran’s nuclear facilities was perhaps the most unpredictable policy choice of his second term so far. The question is whether it will have the desired effect.
The former British Foreign Secretary, William Hague, has argued that it will do precisely the opposite: it will make Iran more, not less likely, to seek to acquire nuclear weapons.
Prof Desch agrees. “I think it’s now highly likely that Iran will make the decision to pursue a nuclear weapon,” he says. “So I wouldn’t be surprised if they lie low and do everything they can to complete the full fuel cycle and conduct a [nuclear] test.
“I think the lesson of Saddam Hussein and Muammar Gaddafi is not lost on other dictators facing the US and potential regime change…
“So the Iranians will desperately feel the need for the ultimate deterrent and they’ll look at Saddam and Gaddafi as the negative examples and Kim Jong Un of North Korea as the positive example.”
One of the likely scenarios is the consolidation of the Islamic Republic, according to Mohsen Milani, a professor of politics at the University of South Florida and author of Iran’s Rise and Rivalry with the US in the Middle East.
“In 1980, when Saddam Hussein attacked Iran his aim was the collapse of the Islamic Republic,” he says. “The exact opposite happened.
“That was the Israeli and American calculation too… That if we get rid of the top guys, Iran is going to surrender quickly or the whole system is going to collapse.”
A loss of trust in negotiations?
Looking ahead, unpredictability may not work on foes, but it is unclear whether the recent shifts it has yielded among allies can be sustained.
Whilst possible, this is a process built largely on impulse. And there may be a worry that the US could be seen as an unreliable broker.
“People won’t want to do business with the US if they don’t trust the US in negotiations, if they’re not sure the US will stand by them in defence and security issues,” argues Prof Norman. “So the isolation that many in the MAGA world seek is, I think, going to backfire.”
German Chancellor Friedrich Merz for one has said Europe now needs to become operationally independent of the US.
“The importance of the chancellor’s comment is that it’s a recognition that US strategic priorities are changing,” says Prof Trubowitz. “They’re not going to snap back to the way they were before Trump took office.
“So yes, Europe is going to have to get more operationally independent.”
This would require European nations to develop a much bigger European defence industry, to acquire kit and capabilities that currently only the US has, argues Prof Desch. For example, the Europeans have some sophisticated global intelligence capability, he says, but a lot of it is provided by the US.
“Europe, if it had to go it alone, would also require a significant increase in its independent armaments production capability,” he continues. “Manpower would also be an issue. Western Europe would have to look to Poland to see the level of manpower they would need.”
All of which will take years to build up.
So, have the Europeans really been spooked by Trump’s unpredictability, into making the most dramatic change to the security architecture of the western world since the end of the Cold War?
“It has contributed,” says Prof Trubowitz. “But more fundamentally, Trump has uncorked something… Politics in the United States has changed. Priorities have changed. To the MAGA coalition, China is a bigger problem than Russia. That’s maybe not true for the Europeans.”
And according to Prof Milani, Trump is trying to consolidate American power in the global order.
