I am currently teaching an on-line course and out topic this past week was contingency leadership / adaptive leadership - essentially, the practice of being able to exhibit multiple styles of leadership. The more chances I have to observe great leaders, the more I am convinced that this may be the most important leadership competency.

Seriously, if you have not recently read some of Fiedler's work or the Vroom-Yetton Leadership Model, this might be a great time to take a look.