Grandparent rights have been significantly eroded since a 2000 Supreme Court decision made it more difficult for third parties to obtain visitation with minor children. However, all states still do recognize some rights for grandparents. A grandparent seeking visitation must be able to prove that this arrangement would be in the best interest of the child and would not cause harm. Some states also require the grandparent to prove that he or she has an actual "parenting" relationship with the child. This might involve the grandparent standing in for a parent for extended periods of time. Such a relationship can be difficult to prove since most people do not keep the type of documentation that can be used to make a case in court. The AARP and the non-profit Grandparents Rights Organization offer informational assistance to grandparents who wish to obtain visitation or custody rights for their grandchildren.