Tbsrk, you took the words right out of my mouth. Get this kid alone and if possible let him swing first and then beat his ass.
Tell your girlfriend that sometimes its neccesary to make difficult choices.
Intimadation is sometimes the better idea.
Of course thats just me. Even if I told my boyfriend to stay out of it there is some part of me that I know would want him to stick up for me.
Of course what Uber said is also right.
You could potentially destroy your relationship with your girlfriend and/or get in trouble with the law.
It's not about whats right or wrong so much but in this case to see the plan and be aware of the concesquences.