As battles of today are fought more and more in various social spaces, the question of "Who fights?" gets more and more intermingled with the question of "Where is the battlefield?".
To make a valid decision, the mind must go through a great feat of balancing and integration. To be successful, the identity holding the mind has to be flexible.
We can observe shifting identities along two different axes:
Shifting identities by responsibility.
This is the royal 'we'. This is the shift of identity in size.
For example, a person in a military or corporate environment can advance through ranks. Greater ranks entail greater responsibilities, and to continue making valid decisions, the mind operates with a higher level of abstractions - and the identity has to learn to integrate such views.
The king becomes the country. The general becomes the army. The CEO becomes the corporation.
Shifting identities by trust.
"I do my part, and I trust others will do theirs." This is the shift of identity in location. This is how a multitude of identities can coexist.
People can trust each other for a vision of 'greater good', or they can trust each other to combat a vision of 'greater evil'.
Examples for the first option would be the construction of social structures/identities such as states or corporations. Examples for the second option would be 'spontaneous sabotage' against such constructions.
Although it's a simple idea, 'identity warfare' can be quite complex and decisive.
The concept of 'control' is rooted in this field.