Timothy M. MacArthur is a Clinical Assistant Professor and Director of the Mason Veterans and Servicemembers Legal Clinic (M-VETS) at the Antonin Scalia Law School at George Mason University. Professor MacArthur brings to the position over 17 years of military experience with the United States Army. MacArthur began his legal career as an active duty Judge Advocate in the United States Army Judge Advocate General’s Corps, where he served as a Trial Defense Counsel, Trial Counsel/Special Assistant United States Attorney, and Administrative and Legal Assistance Attorney. Following his release from active duty, Tim practiced as a Principal Assistant Public Defender in Lake County, Illinois, where he litigated difficult felony cases and was a Public Defender representative to the Veterans Treatment and Assistance Court.

Professor MacArthur has served in various legal positions in the U.S. Army Reserve, including as a Chief, International Law Officer, Brigade Judge Advocate, Ethics Advisor, and Team Chief. Tim’s JAG career has taken him to many places, but perhaps the highlight is 2011 when he was selected to be the Deputy Staff Judge Advocate for Joint Task Force Guantanamo at the U.S. Naval Station in Guantanamo Bay, Cuba. As part of JTF-GTMO, he served as Staff Judge Advocate in the absence of the SJA, worked on JTF-GTMO policies and procedures, oversaw legal aspects of detention operations, served as a SJA liaison to the Joint Detention Group entering the camps and resolving detainee requests, and supervised the daily operations of the JTF-OSJA.

Immediately before joining the faculty of George Mason, Professor MacArthur completed a 2-year mobilization in the U.S Army Office of Soldiers’ Counsel as a Physical and Medical Evaluation Board Counsel representing Soldiers before formal Physical and Medical Evaluation Boards. In 2023, Professor MacArthur received his LL.M. from American University, Washington College of Law in International Human Rights and Humanitarian Law, and his Juris Doctorate from Michigan State University/Detroit College of Law in 2001. He received a Bachelor of Science degree in Psychology from Madonna University in 1998.  Professor MacArthur is a member of the Illinois Bar.