The Hague Convention is a treaty that the United States is a signatory to and aims to keep parents from illegally taking children out of their home country. The goal is to return any children taken to another back to their country of habitual residence. From there, any custody or visitation issues can and should be resolved by a court in that country.
The Hague Convention is important because American court orders may not be recognized in another country without it. Furthermore, countries are generally only allowed jurisdiction within their own borders. As each country is considered to be a sovereign nation, other countries are not allowed to meddle in their affairs. Therefore, the Convention provides a way for countries to partner together to find a resolution to child custody matters that spread beyond the borders of a child's home country.
Any country that has ratified this agreement is required to have a contact point for parents and relevant government agencies to coordinate with. The contact is required to locate children taken against their will and request that they be brought back home. Documents submitted to this authority are admissible in the court of a partner country. In some cases, proof of marriage or parenthood is all that is needed under the Hague Convention to show that custodial rights were violated.
In any child custody case, the best interest of the child is generally the top concern. This can be exacerbated when the child is taken to another country. People who feel that their parental rights have been infringed upon in such a manner may want to meet with an attorney to learn the procedures for filing an application to return under the Convention.