In any organization, there are multiple levels of authority and in every project, the project manager must have some level of authority over team members and available resources. This authority provides a certain level of power. However, exercise authority and authoritarianism are ideas that are far from each other. The first is required to coordinate and use resources efficiently and must be earned. The second generates an adverse work environment that most likely affect the overall performance of the project.
The project manager that search to be a leader can use his authority to manage the project, identify corrective and preventive actions, assess performance and help to grow the team members. This authority may come from a formal designation accompanied by respect acquired based on their experience and lessons learned,
This brings the word "confidence" to my mind.
Authoritarianism on the other hand, is present in those managers who fail to make the team to work voluntarily, Instead they gain control imposing its authority, inspiring fear instead of trust, transforming work in a heavy environment. In other words, discouraging the project team and preventing these members use their creativity for the project. This can arise for various reasons. The fear that another person could highlight or the lack of confidence to delegate are just some of them, but the truth is that this attitude will eventually become self-destructive, because when working in teams is always possible to learn something from others (superiors and subordinates).
Regarding this subject, Albert Einstein said "The worst thing is to educate with methods based on fear, force or authority because it destroys sincerity, trust and only a false submission is achieved"
Under this scenario, it's possible that a project, carried this way, culminates, to some extent successfully, or resulting in failure, but in both cases the lack of confidence of the team members and the working environment generated will eventually generate that the project manager get stuck in their professional and personal growth. Also team members, once acquired knowledge, will seek other opportunities in other companies, and the organization loses the knowledge and experience of such people, besides investing in expenses for additional recruitment and training