Everyone is wondering where Donald Trump's war of words with Justin Trudeau will end. The president and his surrogates have kept up their attacks on Trudeau since his press conference at the G7. It's got a lot of people asking: What is Trump's problem?A surprising number think his actions are simply incomprehensible – the random doings of an unstable person. I disagree and, given the stakes, I think it's worth debating. Trump's attack on Trudeau is a good place to start.Trudeau defends his performance at the G7 press conference by noting that he didn't say anything there that he had not already said publicly or privately to Trump.Trump advisor Larry Kudlow think this sidesteps the real issue. He focuses on the bilateral meeting where the two leaders discussed trade. According to Kudlow, “they were getting along famously…We were very close to making a deal with Canada on NAFTA...”CBC's Rob Russo provides further details. At that meeting, he says, Trump unexpectedly waived his demand for a sunset clause, which was the main obstacle to an agreement. Suddenly, the logjam broke and a deal was within reach. When Trump took off for Singapore, the understanding was that the NAFTA negotiations would quickly resume. Everyone was optimistic.Kudlow believes that at this meeting Trump and Trudeau effectively made an agreement to move on from their differences, but that Trudeau then violated it at the press conference.In Trump's mind, the decision to waive the sunset clause had been a generous act of reconciliation. Yet Trudeau publicly denigrated him just to score political points with Canadians.Trump was livid. He found it duplicitous and humiliating. Indeed, Kudlow claims Trump was even fretting that it made him look weak just as he was going to negotiate with North Korean leader Kim Jong-Un.So, Trump's team is not arguing that Trudeau said something new or different at the press conference. Their claim is that at the bilateral meeting everyone agreed to move on, but that Trudeau then cheated on the agreement. This was the trigger for Trump's tweets.Of course, things look very different from Trudeau's perspective. When he gave the press conference, Trump's decision to waive the sunset clause hadn't yet been publicly announced; and a trade agreement was far from certain. In considering how to respond to questions on tariffs, Trudeau presumably thought it best to stick to his script until things were clearer and more settled.Frankly, I'm with him on this. I don't see how or why this would have compromised Trump or the new arrangements. Had Trump never tweeted, everything would still be on track and by now Trudeau would be talking about a renewed relationship.Nevertheless, Trump genuinely seems to have taken this as a deep personal slight – a betrayal. And so far, he has shown no signs that he is willing to see the situation any other way, which brings us to the key question here: Why not?I'm not sure he can. He may not have the cognitive ability – really. I believe Trump is a narcissist, and I mean that in the clinical sense. Consider the diagnostic signs: narcissists see themselves as above rules that apply to everyone else; they are highly critical of others; they crave compliments and flattery; they speak highly of themselves; they want everything they do to be the biggest and the best; and they are notoriously thin-skinned, which can make them erratic and vindictive.These traits could have been culled from a profile of Trump. They're a perfect fit. The combination of thin skin and vindictiveness is almost his political trademark. When he feels he's been wronged, it is never enough to correct the wrong. He needs to crush those he thinks have crossed him.While these reprisals may be erratic, this doesn't make them incomprehensible or random. In fact, narcissists usually have reasons for their actions – as we see with the reasons behind Trump's vicious attacks on Trudeau.The problem is that their reasons often don't match reality. Narcissists are too wound up in themselves to see things through someone else's eyes. It is as though every situation revolves around them. As a result, they are notoriously bad judges of people and situations; their reasons for their actions often reflect how they imagine reality is, rather than how it is.And that is Trump's basic problem. He imagines that everything that happens is happening to him, when in fact people are often just tending to their own affairs – as was Trudeau at the press conference.This disconnectedness also explains the strange cult-like environment emerging at the White House. Kudlow, for example, is a very experienced and highly accomplished professional who surely realizes that his tirade against Trudeau on Sunday morning TV was outrageous.But Trump has made it clear that if you're on his team, you play by his rules. And that means you see people and situations the same way he does. The result is a growing string of debacles like this one.No one can change Trump, but all of us must live with him. We are quickly learning about the risks this poses for a nation's well-being. These risks must be managed. This doesn't mean obsequiousness or pandering, any more than it means threats or confrontation.It means all governments must be clear-eyed and practical about how they interact with Trump and attentive to the risks that come from getting too close.Dr. Don Lenihan is an internationally recognized expert on public engagement and Open Government. He is currently advising The Ottawa Hospital on an engagement plan to develop its new Civic Campus – a $2 billion, 10-year project. He also co-chairs the Open Government Partnership's Practice Group on Open Dialogue and Deliberation. Don can be reached at: [email protected] or follow him on Twitter at: @DonLenihan