These traits include his obvious need for self-aggrandizement, his overreaction to perceived slights, his tendency to make decisions based on intuition, his refusal to change his views based on new information, his routine carelessness with the facts, his unwillingness to listen to others and his lack of respect for the rule of law.

The dangers that flow from Mr. Trump’s character are not just risks that would emerge if he became president. It is already damaging our national security.