How much monkey business can we tolerate in a leader? What is the connection between leadership and character? Can a political leader with a disreputable character govern wisely? Can a leader be a cad and still be a leader? Some not so nice people still do good work - think of badly behaved artists. Some people are so dedicated to their work they neglect interpersonal relations. We still admire great art or music even if the artist is a disreputable character.
An unethical political leader could, similarly, do a good job of governing a country. It is possible to separate your personal life from your work And having personal problems need not prevent you from governing wisely.
The question of leadership and character assumes that leadership is a role because it is roles that imply responsibilities. Roles like father, mother, teacher, lighthouse keeper, captain, etc all have certain responsibilities. But if leadership isn't a role but an act or impact like influence, then character is not part of the meaning of leadership. If so, we need to say that executives are managers who sometimes SHOW leadership. Thus managers, being role occupants, need to be of good character.
Is there then no connection between character traits and leadership then? Leadership is actually value neutral because we need to explain how criminals and terrorists can also lead. Leadership occurs when people follow, regardless of the leader's character. However, you can't lead certain people on certain issues unless you have the right character. This means that character traits are part of what makes up your abiity to influence people. For example, you couldn't show leadership on stamping out corruption if you were corrupt yourself.
See also Leadership Defined, Leadership Traits, Leadership as Influence, Values and Leadership, and The Purpose of Leadership.