On March 1, Ambassador Don Mahley, the formidable State department nonproliferation negotiator, passed away at his home in Vienna, VA. Don, who had been diagnosed with pancreatic cancer in February 2012, served as the chief US negotiator on the ATT.

I first met Don, a retired Army colonel, in February 2008 on the second day of the first session of the Group of Governmental Experts (GGE) on the Arms Trade Treaty, where I was serving as the UN consultant. The United States was not originally persuaded of the need for a treaty and did not decide to participate in the GGE until the meeting had already begun. Don had the unenviable task of navigating the complex US domestic political landscape as well as a challenging United Nations negotiating process.

Over the next 5 years I watched as Don expertly led the US negotiating team throughout the UN’s ATT process. He traversed the difficult terrain of the United Nations all the while working within the bureaucratic morass of the US government. He instilled confidence in both skeptics of the Treaty as well as its most ardent supporters. In a mere six years, Don turned the United States from a Treaty opponent into a Treaty signatory.

Don was born in Peru, Indiana and attended my hometown college, Purdue University. Our shared Hoosier upbringing and a common love of theater allowed us to pass the stressful and often late night monotony of UN negotiations with good cheer and camaraderie. I fondly remember when we individually attended a showing of Broadway’s Macbeth starring Patrick Stewart, thinking we had each escaped the pressures of the negotiations for one night, only to find that we were inadvertently sharing the experience together.

Don was diagnosed with cancer in the final stages of the UN’s negotiations. But Don didn’t let his illness stop his commitment to seeing the Treaty through. Though he was not able to attend every meeting, his spirit and presence were obvious. The US delegation wanted to see the adoption of a Treaty Don could be proud of.

I visited Don at home a few weeks before he passed. Don used our time together to share his impressions of the ATT negotiations, how they differed from the Biological Weapons Convention process, and what lessons we should learn from the ATT negotiations for future multilateral efforts. I left Don’s house that day knowing I had been incredibly fortunate to have worked with and gotten to really know an amazing man.

Don will be missed terribly by his family and friends, and by his colleagues in the US government and around the world. The impression he left on numerous international agreements has been immense. I was fortunate to get a chance to watch him in action. Don had a common sense approach, always looking for the most pragmatic and least offensive solution to the difficult issues he faced. In the words of Macbeth, “Come what come may, time and the hour runs through the roughest day.”

Photo credit: Hilary Schwab via hschwabphotography.com