The United States has signed, but not yet ratified, this convention. It is an international bill of rights for women.
The convention defines discrimination as the following:
Any distinction, exclusion or restriction made on the basis of sex which has the effect or purpose of impairing or nullifying the recognition, enjoyment or exercise by women, irrespective of their marital status, on a basis of equality of men and women, of human rights and fundamental freedoms in the political, economic, social, cultural, civil or any other field.
The main opposition comes from conservative groups and the religious right who are concerned that the CEDAW will challenge the laws and culture of the US.
The US is the only democracy in the world that has not ratified this treaty.