How can I intervene in a peaceful manner?

My advice is to be honest. Sometimes people aren't going to appreciate it in the beginning but this way you won't have any regrets and eventually they will be thankful. At the end of our lives we regret the things we didn't say rather then the things we did.

First of all let people know that you are not trying to hurt them, and you are not on anybody's side. You just don't want anybody to get hurt. If the show arggession towards you then leave and find other help. Its not worth you getting hurt.

The leading question is your friend. You will learn more about their situation, their thinking, all the while maybe leading them to deeper thought themselves. Ultimately, whatever decision that person makes must be respected and, in most cases, advice from you may need to be curtailed.

I don't feel peace should ever be our goal in life. I believe ferocious courage is what we need. Such power to stand up for what we need and want. That is the kind of power that get's thing done, the power of change.

Trying to be the voice of reason can be good at times but it could also cause you issues. Always determine the situation before you jump in. Do you believe intervening will help or hinder the situation and base your decision on that.

We all experience it at one point or another; somehow we are caught in the middle of a fight between two people we may or may not know. This can be distressing for all parties involved, especially if things are escalating at an alarming rate. At this time, people may not be thinking in rational terms; the Fight or Flight response is in full swing and no one wants to take Flight. The best thing you can do is not panic. Don't add to the emotional turmoil of the scene by yelling or displaying negative body language. Take one person aside and begin to actively listen to what they have to say. When people feel heard, they feel understood and more calm. Next, do the same thing for the other person. This way no one feels like you are picking sides.

You can intervene in a peacemanner by addressing the situation and both parties without being biased.

Sometimes its better to simply be there even if you intervene in a peaceful way if someone's not ready for that it may cause more harm than good. Support and be a good listener and friend when they ready they will come to you!

Politely ( emphasis on "polite") say " excuse me ". Or clearly state you're interrupting and apologizing ," I'm sorry to interrupt, but.."etc

The best way I've seen it is to just tell someone to stop. It doesn't hurt anyone, and doesn't make anyone uncomfortable. If it keeps happening, there's really no peaceful way to stop