It was US president Harry S. Truman who, in the years just after the second world war, kept a little wooden sign on his desk which read: "The buck stops here!". It emphasised his willingness to accept ultimate responsibility for his decisions and actions as president, even the ones that didn't quite work out.

This phrase has since become emblematic of presidential accountability and leadership. Truman wasn't interested in trying to pass the buck, not as a man and certainly not as president.

Interestingly, the sign was made in the Federal Reformatory (prison) at El Reno, Oklahoma, suggesting an implicit moral dimension to this issue of responsibility and accountability. We're all accountable for our actions, whoever we are, but the president above all.

But how things seem to have changed with Donald Trump in the White House.

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Trump continually takes personal credit for any perceived successes as president - fixing global tariffs, Nato members paying more, the Middle East (even taking credit for things that were completed before he took office). But he makes sure that any failures are immediately attributed elsewhere.

He frequently positions himself as surprised or "blindsided" by unpopular decisions, which are always somebody else's doing, somebody else's fault. Subordinates are held responsible. He is not averse to pointing the finger directly at them, and often in public, high-profile settings.

That great loyal Trump supporter, defense secretary Pete Hegseth, for example, has recently been in the firing line for being personally responsible for pausing the delivery of missile shipments to Ukraine. US defence officials had apparently become concerned that weapons stockpiles were becoming low, as they needed to divert arms to Israel to help in the war with Iran.

But the pause in supplying some weapons to Ukraine announced by the Pentagon on July 2 was a hugely unpopular decision that resonated around the world. Hegseth was blamed.

Some have suggested that having loyalists such as Hegseth in critical positions like secretary of defense is highly strategic, and not just for the more obvious reasons. You could argue that having loyal supporters with delegated but overlapping authority is highly advantageous when it comes to the blame game.

Trump can publicly distance himself when things go wrong (as he did here), claim a degree of surprise, and swiftly change course. That way he is publicly reasserting his role as leader without admitting fault.

It is also noteworthy that Trump often reverses these decisions made by his subordinates in high-visibility environments, which suggests a determined pattern of strategic image management.

It's a simple set of moves - you allow a subordinate to initiate a controversial decision, then you rein it in publicly and reassert your authority, thus showcasing your resolve. In other words, delegation to loyal insiders like Hegseth becomes a useful buffer against political fallout.

Loyal insiders still stay loyal (for the foreseeable future at least). They won't sling mud, like some might in their position. So Trump can appear masterful.

But of course, there's more to this than everyday political shenanigans. Personality plays a major role. Some psychologists have argued that not internalising failure is psychologically beneficial.

If you take credit for success but externalise failure, that makes you resilient (and happy). But there are clearly limits to this, and there's a darker side.

People with high levels of narcissism ("I like to be the centre of attention"; "I am an extraordinary person" - both items on the narcissism personality inventory, a method of measuring personalities) often avoid accountability because they perceive themselves as superior to others. But only, it should be noted, in certain "key" aspects of life.

In the words of Jean Twenge and W. Keith Campbell, authors of The Narcissism Epidemic: "Narcissists think that they are smarter, better looking and more important than others, but not necessarily more moral, more caring or more compassionate."

Narcissistic individuals tend to externalise blame to protect their fragile self-esteem and maintain their self-image. They may refuse to admit fault because doing so threatens their grandiose concept of self.

Individuals exhibiting Machiavellian traits, characterised by manipulativeness and a lack of empathy, are also more prone to shifting blame. They may deflect responsibility to serve their self-interest, which is clearly a highly manipulative manoeuvre. You just do whatever is required.

Research also indicates that individuals with low conscientiousness, one of what are considered the "big five" personality traits, are less likely to accept responsibility for their actions. They may be somewhat careless or irresponsible in their work or actions, and when mistakes do occur - which they will - they blame external factors or other people.

In other words, certain personality traits are associated with a tendency to avoid accountability and responsibility.

It has been said that Trump's inner circle consists of loyal sycophants who, even when it's cringeworthy for outsiders, publicly praise him to amplify and protect his self-image. He needs this from them.

But they have another use as well. When things don't go so well, they take it on the chin for him. That's almost part of the job description. When things go wrong, his inner circle all understand the buck really stops with them.