This is when one person sees an injustice or other wrong performed against someone else, and takes up the fight on their behalf.
It's often a mistake.
I used to do this. In retrospect, I can see it was never a good idea. I had this idea of myself as a caped crusader going forth and righting wrongs on behalf of less articulate and less assertive individuals. By performing this immensely valuable service I would ensure that justice, peace and harmony prevailed over the evils of The Man.
I was completely wrong.
First, it's patronising. Who was I to suggest that the individuals whose cases I unilaterally took up were less articulate, and less assertive than myself.
Second, I didn't always ask whether the victims saw themselves as victims, or whether they were in any way concerned about this perceived injustice.
Third, looking back, I think perhaps I had a need to attack the attacker, and I used the poor, unfortunate "victim"s plight as an excuse to launch an entirely different attack on the perceived offender.
I had the opportunity to talk to someone I very much like and respect yesterday. She had the other perspective. As the perceived attacker in a similar scenario, she knew exactly what had been said and how the 'victim' had taken it and was fully informed.
The imagined caped crusader -- not me on this occasion, thank goodness -- had jumped in and launched their attack before even asking whether there was really a battle to be fought. Not only that, but a lot of discussion and information had passed between the two parties who were directly concerned with the incident. The caped crusader was unaware of that communication.
There are cases where it's good to take up the battle on behalf of someone else. My favourite charity, Amnesty International does it all the time. But they do it with the full knowledge and consent of the victims. Those people really are victims and they really do need help.
So yes, I'm still prepared to dive into that phone booth and draw up my underpants, but nowadays I ask if the perceived victim really needs my help. And I try to think about your own motivation. Might it be possible that I'm trying to resolve some of my own issues with the perceived perpetrator?
That's usually enough to stop me making an ass of myself.