There is a difference between people who are narcissistic and those who manifest the particular cluster of symptoms that are labelled Narcissistic Personality Disorder. From Obama's behavior and from what his college colleagues have said about his past behavior I believe Obama has this syndrome. A lot of politicians are merely vain and prideful but they are capable of empathy, understanding the mindset of others and particularly of holding something higher than themselves whether it be values or the country. Like a person with NPD, Obama worships his own image.
Even though I like a lot of what Trump says, I think he is on the continuum somewhere and worry that, if he came to power, he would do whatever he pleases without any sense of loyalty to those that elected him, to the limitations of the office of the President or to the constitution. I think he would trust his own judgment in all matters and I do not know if he has a thoroughly conservative value system. He might economically or even about foreign policy but what about his moral values? I do not think Trump has evidenced a belief in the moral values that I hold as a Christian. In the past, he was pro-abortion but now he claims to have changed his mind. Rather convenient. Also, what is his stance on the role of the Supreme Court. Has he ever expressed a coherent view on their role or the constitution? Why do we have to Google his views on this? Should this not be part of his passion?
Trump is a very, very rich man who is self-made. People like him are used to doing whatever they want. Just like Obama, they are not inclined to take counsel from anyone but their own appointees, not their own political allies or the public at large that elected them. When Obama is about to make a decision shuts his ears and eyes to everyone and everything and does whatever he wants. From what I have observed so far, Trump would do exactly the same thing.