New Mexico is one of the few states that presumes that joint legal custody is in the best interest of a child. With a joint legal custody arrangement, each parent has significant periods of responsibility for the child and the parents work together to make major decisions about the child. But what happens when one of the parties asks to terminate joint custody? How do courts handle that situation? In making their initial determination about custody, New Mexico courts use the “best interest of the child” standard. Many factors go into this determination.