Complex sentence: Previously, he has served as Partner and Executive Vice President for International Operations at Best Associates in Dallas, Texas, Director of International Programs and Development at the RAND Corporation, and directed the RAND Corporation's Center for Middle East Public Policy.
Split into simpler sentences: Previously, he has served as Partner and Executive Vice President for International Operations at Best Associates in Dallas, Texas. Among these positions, he served as Director of International Programs and Development and also director of the Center for Middle East Public Policy.