Leader's main mission is sharing vision. If you don't share the vision, people will all look to different directions and you'll have to correct them at every step with micromanagement.

What if there is no coherent vision in leader's mind? Today's political leaders don't have those grand visions -- they are mostly opportunistic liars playing their games to attract masses. When the real vision is occupying a position, anything that may contribute to this vision is used, including any ideologies or slogans. This leads to pseudo-visions used to align people towards a keeping positions in place.

[Miment]