Anyone can declare themselves to be the 'leader'. But the act of declaration does not confirm anything. Consider the assertions of Gen. Haig after the attempted assassination of President Ronald Reagan. Haig was Secretary of State when he learned of the attempt and boldly declared '...I am in charge...' The US constitution though had already addressed such a situation and Haig was well down the list of candidates. His comments were noteworthy but meaningless.
Though less grandiose in the grand scheme of things, our declarations are likewise without merit if our status is self proposed. In the absence of the affirmation of others, we lead no one and thus we are no more significant than a bell without a clapper. Furthermore, without a common goal or objective, there is no where to lead. Simply staying in place has equal merit to chasing our tails and indeed they are one and the same.
Leadership then is must be viewed as a threefold equation. First, there must be one individual who is recognized as the leader. As long as this individual is appointed in an appropriate and legitimate manner, their skills and qualities are not a topic of debate. Their appointment confers both the appropriateness and legitimacy. Secondly the individuals being led must acknowledge the legitimacy and they must willingly support the individual. Their option, if they oppose the leader, is simple...quit. And finally there must be a common goal which satisfies four criteria. The goal must be legal, ethical, moral and achievable.
These three represent an authentic leadership model. You can now see how leadership is very distinct from being a leader. Leadership is all about the 'we'. Being a leader is all about the 'me', that is, the qualities, characteristics and skills that one brings to the position.
Finally, why is it important to understand this distinction?
Any approach that does not comply with this model is not, by definition, an authentic leadership model. For example, if you speak of a military or other crisis response situation, it is not a leadership model but a command model. If the person in charge seeks no input or exhibits no empathy to the 'followers' then that person is a dictator, not a leader. If compliance comes by virtue of threats or actual harm, that person is not a leader but a tyrant.
What model defines your approach? If you are more likely to be in the commander, dictator or tyrant classification, then there is little wonder why you are not reaching your goals on a consistent basis. Take a long look in the mirror. If all you think of is 'me' and not 'we' then you are falling short...far short...of your responsibilities and getting the type of outcome you have earned and deserve!