Leadership means having to intervene. In all kinds of situations leaders are asked to be judge, police officer, motivator, coach etc. And there is more than one kind of intervention that can be used. You could act to protect the order. You could intervene to motivate someone of help him find his own inspiration.
It can also be necessary to control the direction of a conversation. In the case of a conversation it can be handy to use an intervention model, that takes the different elements of a conversation as starting point.