Emotional Intelligence (EQ) is not only one of the attributes of leadership but differentiates from others by being a key prerequisite to successful leadership.
I will try briefly below to argue the connection.
Leadership is situational (Contingency theory).
To sense and evaluate the various contingencies (situation) a leader finds himself in, the leader must possess a good degree of Emotional Intelligence (EI or EQ) as contingencies are not void of people nor of team dynamics (Path-Goal Leadership theory).
Without EQ, therefore, one would have difficulty in assessing a situation correctly and as a result, one’s response may be lacking or even misdirected.
EQ, thus, forms the cornerstone on which a leader builds his behaviors and actions.
In a similar vein, it may be said rightly that EQ helps a leader assess a situation and choose among the many hats of leadership the right hat to wear when responding, thus constituting an absolute prerequisite for effective leadership.