The Army Lawyer | Issue 4 2021View PDF
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On 2 June 2021, Hays Parks was buried amongst his fellow Marines at the Marine Corps Cemetery in Quantico, Virginia. This was as it should be, for those who knew Hays understood that he was a Marine’s Marine and a proud, vocal member of the Semper Fi fraternity. So, how did this dedicated “gyrene”1 find his way to the Army JAG Corps? And how did he become an internationally-recognized and cited expert and scholar in the field of the Law of Armed Conflict (LOAC) and the definitive U.S. Government voice on essentially all LOAC matters? As someone who knew and taught, worked, and argued with Hays for half a century—or, as the saying goes, “from the beginning”—allow me to answer this question from a more personal, rather than purely professional, perspective.

Hays’s early Marine days have been aptly chronicled by Gary Solis (himself no stranger to LOAC).2 After his graduation from Baylor Law School, Hays entered active duty in 1963 and found his niche as a military prosecutor. In 1968, he volunteered to deploy to Vietnam. Assigned to the 1st Marine Division’s Staff Judge Advocate Office, he was appointed chief trial counsel, where he supervised and tried hundreds of cases. Additionally, he volunteered for, and was appointed as, executive officer of one of the 1st Marine Division’s Headquarters reaction companies, which were assigned to quickly respond to enemy attacks against the unit. It was in this capacity that, in February 1969, through what he later described as a very long night, he led the Marines under his command in repelling an attack by North Vietnam Army regular forces. It was largely this experience—one of functioning as a Marine infantry commander, rather than as a judge advocate (JA)—that helped shape his approach to operational legal issues later in his career.

In the summer of 1972, then-Major Parks was selected by the Marine Corps to attend the 21st Advanced Course3 at the Army’s Judge Advocate General’s School (TJAGSA) in Charlottesville, Virginia.4 It was here that I first met Hays. He was among a class of experienced JAs from the various Services, many of whom had served in Vietnam. Having joined TJAGSA’s International Law Division faculty in January 1972, as a first-term captain, I inherited the somewhat unenviable task of providing international law instruction—to include LOAC—to this seasoned group. Hays approached me early in the first semester, expressing an interest in writing a thesis on a LOAC subject. And, in what I later came to know as his typical, no-nonsense fashion, he advised me that I need not recommend a topic; he had already selected one: “command responsibility.” With the subject thus “decided,” we struck an agreement that I would serve as his thesis advisor.

It was apparent early on that Hays was far more serious than the great majority of his classmates when it came to learning all that he could regarding LOAC—its strengths and weaknesses, as well as its many nuances. His was far from a casual interest. As we worked through drafts of his thesis, I once noted that his approach might be a bit too comprehensive and overly ambitious. Without hesitation, he looked at me, and in his typically straightforward manner, he said, “I disagree. You have to understand that I want this to be the seminal work on this subject.”5 And it was, and remains, just that—even all these years later. This work proved to be simply the first of numerous defining statements on complex LOAC issues that Hays would author during the course of his career.

In the spring of 1973, given the similarity of the legal issues faced by both Services, a decision was made to bring a Marine JA on to the TJAGSA faculty. Hays made his interest in this position known; given his classroom performance and the fact that the individual selected would be assigned to the International Law Division, he was a natural choice. Over the next two years, we shared a second-floor office in the old University of Virginia (UVA) Law School (Clark Hall), lived in the same apartment complex, and came to know each other well. At the time, the conflict in Vietnam was still underway, providing much material for discussion. We spent much of our time debating essentially every aspect of LOAC, from both academic and boots-on-the-ground perspectives.

In a time of long hair and mustaches on the Basic Class students (and much of the faculty), Hays stood in stark contrast. He had a weekly appointment with the UVA barber shop, a perfectly-tailored uniform, and a take-no-prisoners attitude. Basic Class students were both suspicious of and awestruck by this recruitment-poster Marine. Once, after a heavy snow on a cold December morning, Hays—with his back to the students—was writing on the blackboard when a snowball from the back of the room whistled four inches from his head and splashed against the board. In dead silence, he paused, slowly turned, looked at the class, and said, “If a Marine had fired that shot, it would have hit me.” He then resumed writing. Seconds later, the room erupted into applause. Professionally, Hays benefitted significantly from his time at TJAGSA, using those years to delve deeply into the most contentious of LOAC matters and further hone his interest and expertise in this area of the law. Most importantly, however, from a personal perspective, it was in Charlottesville that Hays met Maria Lopez-Otin, a UVA graduate student who became his wife of forty-five years.

I next encountered Hays in the summer of 1979, during my assignment to the International Law Division, Office of The Judge Advocate General (OTJAG). After his time at TJAGSA, Hays held positions at the Office of the Secretary of the Navy, serving as a congressional liaison, as well as in the International Law Division, Navy OTJAG, where he headed the Law of War Branch. Following these assignments, to the great surprise of many, he made the decision to resign his regular commission, choosing to remain in the Marine Reserve. To those who knew him, however, this move made perfect sense. He was offered the opportunity to assume the civilian position in Army OTJAG’s International Law Division, previously occupied by Wally Solf,6 and to serve as the Special Assistant for Law of War Matters to The Judge Advocate General. We arrived at OTJAG within two weeks of each other. And again, for the next seven years, though Hays focused exclusively on LOAC matters, we dealt with, discussed, and debated a wide range of legal issues associated with U.S. military operations. It was during these years that Hays systematically began to position himself as the fount of LOAC expertise within the Pentagon—an expertise that the Department of State soon recognized as well. His academic reputation was enhanced during these years also, as he was selected to serve as the 1984–1985 Stockton Chair of International Law at the Naval War College. Our frequent conversations over this time resulted in the office establishing a physical presence in—and providing daily legal advice to—the Army Operations Center, and the concept of a unique legal discipline focused exclusively on the conduct of military operations was conceived (later implemented as Operational Law).

Upon my return to OTJAG in 1994, as the Chief of what was then the International/Operational Law Division, Hays had firmly established himself, both domestically and internationally, as the singular U.S. Government spokesman on all matters dealing with LOAC. He had authored definitive opinions or articles on subjects such as assassination and targeted killings, the concept of “unnecessary suffering,” perfidy in combat, the wearing of enemy uniforms, and LOAC applicable to air war. He had exercised primary responsibility for the investigation of Iraqi war crimes during that state’s 1990–1991 occupation of Kuwait and had served as a principal U.S. delegate for various LOAC negotiations in New York, Washington, Geneva, The Hague, and Vienna. He was frequently called upon as an expert witness in terrorism cases in the United States and Canada; had provided LOAC-related testimony on Capitol Hill; and was a frequent lecturer at every Senior Service School, as well as at many other U.S. and foreign venues. Along the way, the operational Hays had also managed to collect an impressive array of U.S. and foreign jump wings and sharpshooter badges, and had risen to the rank of Colonel in the Marine Corps Reserve—accomplishments that further served to burnish his credibility with war fighters worldwide.

During my eight years at OTJAG, Hays continued to write, opine, serve as an adjunct professor at George Washington University and American University Schools of Law, and represent the United States in numerous international negotiations. The month rarely passed when he was not traveling abroad, testifying, or lecturing. His work continued to be cited in essentially every law review article dealing with a LOAC topic. When a LOAC issue arose within either the Chairman’s Legal Office or that of the Department of Defense (DoD) General Counsel, the question inevitably asked was, “What does Hays say?” Solely responsible for the legal review of proposed Army weapon systems, he consistently dedicated considerable time and effort to this task, and the resulting memorandums on scores of such weapons were unfailingly comprehensive, but always readable. Perhaps his most favored client was the Special Operations community, which he advised from 1979 until his retirement; theirs was a mutual respect. The U.S. Special Operations Command recognized Hays with exceptional honors in 2001 and 2006. And, as always, during these years, Hays continued to work tirelessly on drafting and coordinating, within the DoD, the production of a much-needed replacement for the Army’s 1956 Field Manual 27–10 dealing with the Law of Land Warfare—a DoD Law of War Manual for which he had become the singular driving force.7 We debated, and sometimes disagreed; but we always arrived at a way ahead on matters for which Hays, and the office as a whole, were responsible.

After twenty-four years of extraordinary service, Hays departed Army OTJAG in August 2003 to join the International Affairs Division of the DoD Office of General Counsel. As Chair of the Department’s Law of War Working Group, his primary goal was the completion and publication of the DoD Law of War Manual. By now, it had been an ongoing project for almost three decades. Despite his best efforts, however, it was not to be. With a final draft of the Manual finally in hand, politics intervened. Following the 11 September 2001 terrorist attacks, the U.S. Government issued a number of highly questionable interpretations of LOAC’s application to various aspects of its “Global War on Terrorism.” By 2003, there was a push by certain non-DoD agencies to revise the draft Manual to reflect these newly-conceived views. Consequently, upon Hays’s retirement in 2010, the mandated substantive re-write of significant portions of the Manual was still a work in progress. Its publication would not occur for another five years. And, while the Manual makes no mention of the indispensable role that Hays had long played in its development, those who were involved in this initiative over the years are fully aware that, if not for his decades of herculean effort, the Manual would never have seen the light of day. It is only fitting that his name appears in its footnotes more than that of any other individual.

Hays was not without his critics. He could be opinionated, stubborn, and, at times, unduly confrontational. He was also the U.S. Government’s most skilled and effective advocate on LOAC matters. Those who disagreed with his views and chose to challenge him in international fora came to understand that they must come exceptionally well-prepared to do so; for, over the years, they witnessed him systematically shred positions taken by their fellow delegates. His approach toward LOAC issues was driven by his unmitigated, oft-stated, desire to shield the U.S. warfighter from unwarranted and potentially life-threatening restraints on the means and methods of waging armed conflict. In the years following his retirement, he focused his efforts on producing a book discussing a subject about which he had developed a practiced and frequently-called-upon expertise—ballistics. He was in the midst of extensive research for this book when he passed away. He assured me, as he had regarding his Advanced Class thesis fifty years earlier, that it would be the “definitive” work on this subject. I have no doubt that it would have been. So, Semper Fi, Hays. We look back on all that you accomplished with the deepest of professional and personal gratitude and respect. You were truly one of a kind. TAL

Mr. Graham is the former Chair of the International/Operational Law Division, TJAGSA, the former Director of the Center for Law and Military Operations, TJAGSA, the former Chief of the International/Operational Law Division, OTJAG, and the former Executive Director of the Judge Advocate General’s Legal Center and School. He retired as a Colonel from the U.S. Army.


1. The word “gyrene” is slang for someone who is in the U.S. Marine Corps.

2. Gary Solis, Hays Parks—A Legacy, Lieber Inst. (June 4, 2021),

3. This course is now known as the Graduate Course at The Judge Advocate General’s Legal Center and School in Charlottesville, Virginia.

4. This followed after a number of assignments post-Vietnam, to include duty at Camp Pendleton, California.

5. See generally Major William H. Parks, Command Responsibility for War Crimes, 62 Mil. L. Rev. 1 (1973).

6. Colonel (Retired) Solf occupied a civilian position within the International Law Division, OTJAG, for many years. He was a principal U.S. delegate to the international negotiations that produced the Protocols Additional to the 1949 Geneva Conventions. The annual Solf–Warren Lecture at The Judge Advocate General’s Legal Center and School honors his many contributions to the Judge Advocate General’s Corps.

7. U.S. Dep’t of Army, Field Manual 27–10, The Law of Land Warfare (1956).