Aran Bright wrote:
There are many discussions about what is the right and wrong thing to do in a fight, but I wanted to know, when is it the right time to step in, to intervene?
To begin, you should find out what the law, both criminal and civil, says about self-defense and defense of others. When (if ever) does the law permit you to intervene? How much force may you use? If the assailant tries to retreat, what does the law allow you to do?
Next, you should talk about this with friendly members of your local constabulary. The police I know all tell me that one of the most challenging tasks they face is stepping in to stop an act of domestic violence, because often, the victim will turn on the police when she (or he) sees the police using force on her (or his) spouse.
Also, remember that it may not be clear just what is happening. A couple of years ago, a friend and I were on our way home from an aikido seminar when we saw a woman struggling with a man on a side-street. We pulled over, jumped out of the car, and ran toward the couple. I hollered at the man to stop and shined a bright flashlight in his eyes, while my friend yelled for the police. It turned out that the two were a couple of pot-heads fighting over the location of their stash. They kissed and made up quickly, the woman assured us that all was well, and asked us (nicely) to leave them alone. The police didn't show up in the fifteen or so minutes we were there, by the way.
As for the right time to intervene, that seems easy: as early as possible while maintaining a position of maximum advantage. As one of my firearms instructors put it, "Shoot as quickly as you can, but as slowly as you must. You can't win a gunfight by missing."
I hope this is helpful.