I recommend the reading of a very interesting article by M.D. Edward M. Stephens:

”Rye Hospital program for treating children affected by Parental Alienation Syndrome (PAS)”

by Edward M. Stephens, M.D.

I quote his introduction from his presentation:

Introduction:

Intense interest in the well-being of children during the divorce process has led to an evolved understanding of the best interest of the child (BIC). New BIC standards go beyond financial support and securing their safety from physical harm and extend to the protection of the psychological well-being of the child. Absent a clear finding of fact that a parent is unfit to do so, it makes good sense that both parents participate in the child’s life after the break up of the nuclear family. In other words, the BIC is now understood by judges, evaluators and therapists to mean the inclusion of both parents in the child’s life after the divorce.