Trump believes he is always the smartest person in the room.

He listens to nobody's opinion unless it is in complete agreement with his own. He is smart enough to run his own privately-held businesses, sometimes even to profitability. He is smart enough to use debt-based financing to generate income for himself at a great cost to others.

He is, however, not smart enough to recognize that he is surrounded by people who are much smarter than he is, who are more knowledgeable and who have long experience in areas where Trump has none.

His failure to recognize that others are smarter and know more than he does is his largest deficit. He is just smart enough to get along, but not smart enough to know his own limitations and use the advice given to him by those who know more than he does.

In the end, Trump is not very smart at all, as evidence demonstrates. In the end, he is not smart enough to know that he's not smart enough to be in the position he is in. That endangers us all.