Leaders and Managers: Followers Create the Former, Power the Latter

For the typical person involved with any sort of work-oriented organization, the difference between managers and leaders will be a subtle thing, if most people even can describe the two types of roles precisely. 

Some might say the difference is between informal and formal forms of management. The president of the United States "leads" by formal mechanisms. He or she has power, the authority to command, by virtue of holding an office. 

CEOs, priests, legislators, judges or any other officials you can think of who have power by virtue of holding an office provide other examples of formal power. 

Anybody who has been in combat knows there is another type of authority, exercised informally, irrrespective of rank. That is a classic case of "leadership," which might be said to be an informal source of power, not granted by rank or office. 

Other examples often occur in voluntary organizations, where some people exercise leadership by personal traits or charisma that are unrelated to any formal title or official role. 

One can "manage" without charisma or personal authority, because of the "bureaucratic" grant of authority of office. 

One cannot "lead" without the ability to inspire informal assent to one's leadership. Paradoxically, leaders are those whom followers designate, and not those whom the formal structures of power designate. 

Managers and leaders are not identical concepts. 

In a formal sense, one must follow legitimate orders of a manager, executive, judge or other official because that person has the legal or institutional authority to issue an order to you.

Leaders get followed because people trust the leader's authority, expertise and personal and charismatic traits. In some cases, a leader has no formal grant of authority save that granted by the followers. 

And the two types of authority can be mixed, in most cases. Conceptually, one can lead without managing, in the specific sense of exercising genuine authority without formal designation (think of sergeants, petty officers or corporals in small group combat, especially when the lieutenant has been killed).

 It is possible to manage without leading (we do what you say because you have the power to order us to do those things). One can be a "poor" manager, but still be a manager, in terms of formal authority. 

In some cases, a manager might also be a leader (we follow because we believe in you, not just because you have the right to command). 

In other cases, followers designate their own leaders. That is why successful commissioned officers rely on their non-coms. 

You might argue the most successful authority figures are those who have both legal power and the informal assent of those they lead. "Office" confers power. It does not confer active assent or enthusiastic and creative support.

Volunteer organizations routinely rely on informal leadership; they have to. Large enterprises normally are managed.