The job of a leader is to schedule meetings, and the good ones actually manage to get people to show up. Leadership is about herding cats, not about technical expertise.
In the US, "Herding Cats" often means trying to get a group of highly individualized people, into a unified direction.
Then, there's this EDS ad: https://www.youtube.com/watch?v=m_MaJDK3VNE
The role of a leader is to be a force multiplier on the rest of the team, regardless of who decides the objective.
It is often the case in contract work that the project owner is the client, and the leader is the head of the contracting team. The leader depends on the project owner to provide clear objectives, so that they may use them to effectively direct their team in accomplishing them. However, it applies within organizations as well, where the owner of a project may be on the business side, whereas the team leader is on the infrastructure side.