In 1993, governments around the world agreed to a landmark arms control treaty, the Chemical Weapons Convention. It prohibits countries from building chemical weapons, using chemical weapons and requires countries to destroy whatever stockpiles of chemical weapons they may have.  The way treaties like this work is that governments come together every few years for what are known as "Review Conferences" in which they assess past progress and set priorities for the coming years.  In the middle of May, members of the Chemical Weapons Convention gathered in The Hague for a five year review conference. And that is where things hit a few snags, according to my guest today Mary Wareham.  Mary Wareham is the advocacy director of the Arms Division of Human Rights Watch. We kick off discussing the history and some successes of the Chemical Weapons Convention. We then have a longer discussion about the complicated diplomatic dynamics of maintaining an an effective ban on chemical weapons use and development.