Is Passion a Necessity When It Comes to Great Leadership?

I've often said that "leaders are passionate about whatever they're leading." Is this true? What is passion, and is it a necessary component of great leadership?

I answer this question with a resounding "YES!" Rosabeth Moss Kanter said that “leaders share their passion.” I think this implies that a leader should have "passion." Right?

A dictionary definition of passion is "any powerful or compelling emotion or feeling." Synonyms include fervor, fire, zeal, and ardor. I would conclude, then, that a good leader should be easy to spot. Right? After all, how would one hide their zeal, fire, or fervor about a task, project, or calling? So, when a great leader is present, it should be obvious to all.

I remember reading somewhere (Good To Great maybe?) that a "level 5" leader exhibits a blend of personal humility and sheer will. This is probably as good a definition of great leadership as any. A great leader will be very humble while at the same time being very much "on fire" for the cause.

As a result, good leaders can be hard to understand. The passion of a great leader won't show over personal issues. But threaten or otherwise affect the organization, and watch the passion come out.

I've been around many in management positions that never got excited about anything. What did this say about their leadership? Where was the passion?