Mary Stata works at the Friends Committee on National Legislation, where she leads the Peaceful Prevention of Deadly Conflict program. Mary lobbies the U.S. government to invest in non-military tools that help prevent violent conflict before it starts. Mary also leads the Prevention and Protection Working Group, a coalition of over 30 human rights, humanitarian, religious, and peace organizations dedicated to improving US capacities to help prevent mass atrocities and protect civilians threatened by it.

Prior to joining FCNL, Mary worked in India and Washington, DC for Mennonite Central Committee – a relief, development, and peacebuilding organization that operates in over 60 countries around the world. While in India, she taught English and worked at a women's center. Most recently, Mary's advocacy work in Washington focused on conflicts in central Africa, HIV/AIDS policy, and foreign assistance reform.