Get her to send out the general invite and to wait and see who comes to her house. Don't make too big a deal about it. She is already calculating the pluses and minuses here. This is a very good lesson in loyalty and friendship for her If the majority don't turn up because they dislike her friend, she will quickly learn that close friends are more important than going with the herd. If your daughter decides to not invite her friend, she herself is joining that herd. Point out to her as simply as possible the moral dilemma of her position, and ask her to do what is right, but let her come to the decision on her own. Kids have a very strong sense of justice and fairplay. This is a very interesting scenario playing out here, and sensibly handled will contribute greatly to her development. Good luck with it!