what is law enforcement required to do when another parent refuses to abide by a parenting plan in state of WA

The parenting plan is a court order directed to the parents of the child. The police is not required to enforce the parenting plan. Most police department likely would decline to get involved in a parenting plan dispute unless there are allegations of criminal activities.

Parents who do not abide by the parenting plan without good causes may find their parental rights severely restricted by the judge. Using the children as pawns in parental disputes is generally disapproved by the judges.

Parents who believe the other parents are not following the parenting plan may bring the issues before the court.