Obtaining a passport for a minor in the US requires both parents. You'd would have to get a court order giving you custody. *Being granted sole legal custody does not necessarily mean the custodial parent can remove a minor child from the US. If the court grants sole custody to one parent and visitation rights to the non custodial parent permission to take the child out of US would need to be granted by the court. The matter might be the jurisdiction of a state or federal court depending upon the resident or citizenship status of the parents.