^^^ They can't ratify it otherwise they'd get pinned for the whole, 'no child left behind' debacle.
The 'home of the free' has the least freedoms of any western nation. Domestic spying, draconian drug laws, amazingly punative tax evasion penalties, and the highest prison population by FAR are just a few examples of this.
In the U.S. defense, I don't know how much this convention really does though...