Dr. Alan J. Lipman has been a professor at Georgetown University and The George Washington University, and has held positions at Yale University School of Medicine and The Hospital of the University of Pennsylvania. He is the founder of The Center for the Study of Violence and Washington Psychotherapy. The views expressed are his own.

(CNN) Donald Trump's statement in the final Presidential debate that he would leave the nation in suspense over whether he would accept the election result is merely the most recent example of the narcissism that has marked his candidacy. But while some might be tempted to dismiss such remarks as simply bluster, their extremity and breadth reveal something fundamental -- and critical -- about how a President Trump might perform in office.

As a clinical psychologist, I have worked with many narcissists over the past 30 years, and have taught how to detect and treat such behavior. That's why it isn't hard for me to spot some of the signs, even from a distance, in Donald Trump.

For a start, there is the severe inability to focus on consequences other than those which directly affect him. There is a significant lack of empathy for the nation, and the impact that personal decisions made in rage would have upon the nation and its citizens. There is also the impulsivity with which Trump makes decisions of sweeping consequence, as well as the inability, even with the most stringent preparation, to prevent eruptions. All of this suggests narcissism. And together these traits make the candidate profoundly unfit for the Presidency.

The reality is that being president requires both discipline and self-discipline. Given the constant flow of expected and unexpected events that beset a president -- crises, demands, new threats and circumstances demanding immediate yet thoughtful and informed response -- he or she must have the ability to focus on each new situation without being distracted by personal slights, arguments and vendettas.

Trump, though, has shown himself to be markedly impulsive, to the point that those who have worked with him have reportedly found it difficult to guide him to focus on essential preparations and learning. This belies the much touted idea by supporters that he would be guided by experts. He is instead guided by impulse, the search for praise and vengeance, and the wish for personal grandiosity.

Trump's ever-present need for praise, meanwhile, makes him extremely vulnerable to manipulation; look to his response to Russian President Vladimir Putin's actions . Of greater significance is his draw to conflict. Once engaged, he finds it extraordinarily difficult to pull back for fear of a loss of perceived power, a trait that would be easily provoked in a host of foreign and domestic policy situations.

Such threats to his opponent point to another deficiency in Trump's personality. The presidency requires the ability to tolerate and synthesize disagreement -- to forge highly different and conflicting points of view into actions that are best for the nation, even if they differ from one's own. Indeed, the capacity to listen to strongly held differing opinions, without rage at disagreement is critical to forging effective decisions and policy.

But Trump, throughout his career, has been noted for his inability to tolerate disagreement, erupting into uncontrolled rages in the face of any slight. This has been revealed time and again on the campaign, not least in his obsessive tweeting about pageant contestants in the early hours of the morning.

This trait has particular implications with regard to a free press. Trump apparently does not understand or tolerate the essential role of the press as a check on presidential power. Rather, consistent with the manner with which he has made use of the press in his prior sales work, he regards them as a type of personal publicist, who should provide praise, and otherwise should be open to abuse.

During the campaign, Trump has banned some reporters from press conferences. He has also called on his audience, and the broader public, to treat the press with the same disdain he has shown toward it. This contempt for the media, combined with his expressed admiration of leaders such as Putin and Mussolini and his inability to tolerate dissent raise the specter of a president who would think little of repressing a free press.

More broadly, a president must have an authentic vision for America. Typically, this has been developed through interest in and study of foreign or domestic policy throughout one's life. This vision provides an anchor and guidepost for the many actions that a president will take. Yet during his 70 years on this Earth, Donald Trump has had no real experience in foreign or domestic policy, his efforts instead focused on pleasure, securing greater attention for himself and making money.

Finally, a president must have empathy -- not merely to manipulate those who can be used for one's own benefit, but an actual understanding of, and care for, the people he or she wishes to govern, regardless of race, gender or creed.

Ultimately, the purpose of the presidency is to serve the American public, not merely to add a new trophy of self-admiration to a shelf that can never be filled. But Trump has an extraordinarily cynical contempt for the public in this regard, a social Darwinistic philosophy that all must fight in a Manichean struggle to win; that he alone can and should win; and that views the presidency as a vehicle for that personal victory.

His willingness to adopt and/or exploit elements of any ideology -- white nationalism, anti-Semitism, racism, misogyny -- is an indicator of this cynical view. It is an approach based upon the narcissistic wish to take what he wants, and to break the rules in doing so, whether that be breaking contracts or the rules of personal consent, defying the usual definitions of decency and truth, or belittling the essential structures of elections and a democratic republic. All this not in the interests of nation, but of self.

In his search for satisfaction through conflict, deception, and self-glorification, Donald Trump is utterly blind to the actual needs of the other. And he will not find this satisfaction in the presidency, because he will meet the same disagreements, failures of praise, slights and disapproval that he has met elsewhere.

At a news conference in May, he responded to reporter questions of his actions with an over half-hour attack on the press. His behavior was described by the New York Times as "a level of venom rarely seen at all, let alone in public, by the standard bearer of a major political party." He was most puzzled by why the press was not praising him, rather than asking him questions. He appeared not to realize that ensuring Presidential accountability, rather than providing supplication, was role of the press in a democratic republic. In this expectation, according to Kathleen Hall Jamieson, Trump appeared to be making a a fundamental presumption "that was so faulty as to be bizarre" In a system characterized by separation of powers, and checks and balances upon that power. It is an assumption that Trump has made throughout his career, and one that he has promised to continue if were ever to gain power.

The problem for Trump is that no one can ever find complete agreement, can ever receive constant fealty and admiration. This has been the wish and the downfall of dictators and nations through the ages. Their ashes lay beneath our feet.

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Yet here is Trump, consumed with every trivial slight. A man who lacks empathy for the consequences of his actions upon broad swaths of the American public. A man with a fundamental need for conflict and with a remorseless willingness to use the most destructive tools of society towards those with whom he disagrees and who he feels have betrayed him.

Bereft of knowledge, of the empathy that drives and is essential for actual service, Trump is willing to act upon impulse, without knowledge, and is driven by fury. He is a candidate with the potential to bring a democratic republic down with him.