Together with Somalia and South Sudan, the U.S. has not ratified the Convention on the Rights of the Child. I think the reasons for Somalia and South Sudan are quite clear — Somalia has not had a functioning government in decades, and South Sudan is simply too young a nation to have signed and ratified all those important treaties yet.
The Wikipedia page on U.S. ratification of the Convention on the Rights of the Child cites a number of arguments used by political opposition to ratification in the U.S. However, the page also states that:
[President] Barack Obama has described the failure to ratify the Convention as 'embarrassing' and has promised to review it.
What would be required for the U.S. to ratify the Convention on the Rights of the Child? Is this up to the President or is it Congress that decides? And has it not been ratified because a majority opposes ratification, or because it simply hasn't been put on the agenda out of low priority?