A strong antonym for "dictator"?

Is there a formal antonym for the word "dictator" other than " democratic" to describe a school principal?

Pluralist:

• a ​person who ​believes that the ​existence of different ​types of ​people, ​beliefs, and ​opinions within a ​society is a good thing.

Cambridge Dictionary

Consider, collegial

Having authority or power shared among a number of people associated as colleagues

Collins English Dictionary

On screen, his persona is as flat and colorless as his home state of Indiana, although around the office he's more like a collegial headmaster, chatty and amiable, yet demanding objectivity from co-workers even when they talk politics by the water cooler. (Source: LA Times)