The U.S. is the only country in the world that has signed but not ratified the United Nations Convention on the Rights of the Child (UNCRC). Opposition to ratification in the U.S. often centers around concerns about national sovereignty, parental rights, and the fear that international standards could conflict with U.S. law and family practices.
However if you read the UNCRC, the protections to prevent ppl from marrying children, force children to have babies and the child work laws seriously protect children. This will guarantee the rights of children are protected under international law. Further, it helps to set a Federal president and aligns the USA with the global community on issues that are a priority internationally.