Hays Parks—A Legacy


| Jun 4, 2021

Hays Parks

The influence of William Hays Parks on the law of armed conflict (LOAC) goes back over 50 years and his fingerprints will be imprinted on it for a long time to come. A giant in the field, he was dedicated to providing U.S. combatants with the most effective means available and committed to the development of the law of armed conflict, in equal measure.

Do you want to know about the U.S. position on assassination and whether targeted killing is assassination? See Executive Order 12333 (1989), first signed by President Gerald Ford and re-issued by every succeeding president. Hays Parks wrote the foundational sections of that seminal Executive Order. Is there a “test” to determine what constitutes “unnecessary suffering”? Yes. Read Hays Parks’s article on the “Joint Service Combat Shotgun Program” in the October 1977 issue of the Army Lawyer. Hays formulates an easy-to-understand rule. How about the problem of direct participation in hostilities and that pesky “for such time as” requirement? Read Hays’s masterful interpretation of that phrase, along with his informed discourse on other foundational law of armed conflict issues, in his 2010 International Law and Politics article. How about command responsibility? In 1973 Hays’s sweeping 104-page recitation of that topic, from Sun Tzu to Lieutenant Calley, remains relevant and current fifty years later. Perfidy in combat? Wearing the enemy’s uniform? Air War and LOAC? Hays has written major articles on those and scores of other LOAC topics—and they’re written damn well.

Early Career as a Judge Advocate

Hays received his bachelor’s degree and juris doctor from Baylor University. Upon graduation from law school in 1961 he entered active duty as a Marine Corps judge advocate. With “constructive service credit,” and its gift of time-in-service/time-in-grade, he was advanced to the grade of captain and began working through various positions in a Staff Judge Advocate’s office. Early on, he gravitated to courts-martial, where he excelled as a military prosecutor.

Hays deployed to Vietnam in late 1968, after having volunteered while a Camp Lejeune judge advocate. By then he was a seasoned trial lawyer. He was assigned to the 1st Marine Division’s Office of the Staff Judge Advocate, housed in two adjacent Quonset huts at the Division command post on Hill 327, a few RPG shots southwest of Da Nang.

One of Hays’s earliest in-country cases involved a currency ring of three Khe Sahn Marine deserters who had joined a band of Army deserters in Saigon. It was a tale Hays often told. The group financed a comfortable life-style with postal money orders purchased with bad checks. A lot of bad checks. When the three accused Marines were eventually apprehended by Army CID, Hays was detailed to take custody of them and herd them to the Marine Corps’s DaNang brig for pre-trial confinement. Hays caught a flight to Saigon, showed his orders, and signed for the three accused. After introductory niceties, Hays realized he had a shotgun but no handcuffs. (Flex cuffs had not been invented yet.) After a brief pause, Hays recalled, “I made each Marine remove his boot laces and belt, and loosen his trousers to the point that they would fall down unless he held them up.”[1] His prisoners thus encumbered, the Saigon-DaNang flight to the brig, with Hays holding a loaded shotgun, was uneventful.

Shortly into his thirteen-month tour of combat zone duty, Hays was appointed Chief Trial Counsel—the 1st Marine Division’s lead prosecutor. It was a busy period when all the military branches were suffering wholesale desertions, record drug use, and violent racial problems. In 1968, 148 Marine Corps general courts-martial and 1,284 special courts-martial were tried in the combat zone. No matter how you cut it, it was a lot of work for few judge advocates working in field conditions, with court recesses due to in-coming fire, no dedicated transportation, iffy electricity, and four-holers. Hays received the Navy Commendation Medal in recognition of his work.

Defense of Hill 327

Mid-February 1969 was the beginning of Vietnam’s annual Tet holiday. As an additional duty, Hays volunteered and had been appointed executive officer (second-in-command) of one of the 1st Marine Division Headquarters’ reaction companies. The reaction company was an ad hoc, understrength company comprised of headquarters personnel who were assigned to meet the frequent probes and attacks on Hill 327’s division headquarters.

Tet usually meant an enemy attack. Sure enough, although not as heavy or widespread as the infamous 1968 Tet offensive, enemy sappers attacked the 1st Marine Division command post in strength. They were North Vietnamese Army troops, not Viet Cong irregulars—it made a difference. Throughout the night Hays was in his desired element. He led his Marines in an all-night firefight that routed the surviving enemy shortly before sun-up. Hays, ever after, took justified pride in his part in the night’s heavy combat on Hill 327, not as a judge advocate, but as a Marine infantry commander.

Post-Vietnam Years

Two years later I first met Hays at Camp Pendleton, a post-Vietnam duty station. Even as a major-select, he already was … shall we say, a “colorful” character. He was a fount of good stories, an aggressive litigator widely known to be fast on his feet in a trial, and smarter than hell. Through means I have never discovered, he was transferred to the Army’s Judge Advocate General’s School, in Charlottesville, Virginia, where he became the first Marine to be assigned as an instructor without first having been a student.

The Vietnam conflict over, Hays’s star continued to ascend. Assigned to the Office of the Secretary of the Navy, he served as SecNav’s congressional liaison. Then, assigned to the Office of the Judge Advocate General of the Navy, he was appointed head of the law of war section. His initial writings on LOAC had been published by this time.

Sometime during this period Hays managed to earn highly coveted Navy-Marine Corps jump wings. Virtually all career Marine judge advocates had, at one time or another, requested orders to jump school at Ft. Benning’s Army Airborne School. No desk-bound Marine JAG ever got those orders approved. Except Hays Parks. He would eventually add Army Master Parachutist wings, as well as British and Canadian jump wings, to his airborne accomplishments.

I recall a dinner at Headquarters Marine Corps for the world-wide caucus we Marines used to hold each year in Washington D.C. That year, Hays announced he was resigning his regular commission to take civilian status and a Reserve commission. Knowing how gungy he was—Army folk would call him seriously “strac”—I asked Hays, why? Why give up a promising Marine Corps JAG career to be a (heavy frown) civilian? As I recall, his response was something about “law of war” and its importance. Somewhere, Hays had divined his life’s work, the coming attention to law of war, the path upon which he would excel and become a national authority and, in some circles, an international force for LOAC.

He resigned his regular commission and never looked back.

Special Assistant for Law of War Matters

I lost track of Hays for a while until, in July of 1979, he was appointed Special Assistant for Law of War Matters to the Judge Advocate General of the Army. He held that high visibility, high responsibility position for the next twenty-four years, until August 2003. And what a career he made of it! Through the rise of the Additional Protocols, 9/11, and “unlawful combatants,” Hays regularly represented the United States in law of war negotiations in Geneva, Vienna, and The Hague, as well as in Washington and New York. He was a law of war expert witness in numerous U.S. and international criminal trials, gave testimony on Capitol Hill, and was a widely called-upon speaker.

His participation in a variety of domestic and international meetings, forums, and conferences only added to his already broad base of LOAC-related experience and expertise. Hays could discuss the fine points of conference players’ positions, argue details of multi-national treaties, conventions, and agreements, and parry opposition to U.S. primacy, because he had been there! He had heard the views and arguments of other States while pressing the U.S. position. He had played a part in their formation.

His effectiveness on the international stage didn’t mean he abandoned his own career, however. Granted academic leave, in 1984-85 he was the Stockton Chair of International Law at the Naval War College where he influenced the minds and careers of other promising Navy and Marine officers. He lectured at all the armed services’ higher schools. At the same time, he was no less forthright in questioning authority and tradition. The iconoclastic tenor of his writings during this period can be seen in their titles: “Deadly Force is Authorized,” “Special Forces Wear of Non-Standard Uniforms,” and “Righting the Rules of Engagement,” for example. With Hays the questioning mind was genetic.

Article 36 Weapons Reviews

Hays told me more than once that the duty he most enjoyed as Special Assistant for Law of War Matters was writing Article 36 conformance reports for new weapons the United States was considering adopting. Indeed, his Article 36 reports are among his most interesting writings—relatively brief, accessible to the military or civilian reader, with interesting and cogent background material leading to Hays’s ultimate recommendation. Laser weapons, drone munitions, the combat shotgun, cluster munitions, flechette rounds, depleted uranium, and many more fascinating Article 36 reports—some of which are available on the Internet—remain markers for his broad law of armed conflict background and clear writing. His reports incisively interpret law of armed conflict requirements—and often highlight its allowances.

I have sometimes described Hays as The Man Who Never Met a Weapon He Didn’t Like. He took it in good humor, but it was an unfair quip. Yes, he did sometimes seem to lean toward finding new weapons to be Article 36 compliant. But, it was because he wanted U.S. warfighters in armed conflicts—international or non-international—to have the most effective, most reliable weapons possible within the constricts of the law of armed conflict. His Article 36 focus was always on the wounded private or lance corporal facing a fast approaching enemy assault, as well as on the legal mandate of Article 36. No one ever charged Hays with looking for ways to keep a new weapon from the U.S. arsenal. But neither can anyone accuse him of ever shading or evading the law of armed conflict’s requirements either.

And we never heard of the weapons he found to be non-compliant.

Review of Open-tip Rounds

Few Article 36 reports have been more heavily contested, or more important to Hays, than the one leading to U.S. adoption of open-tip small arms ammunition. Open-tip rounds have a very small aperture in their nose that affects external ballistics and enhances long range accuracy. Snipers in all U.S. military services use them. They are not the “hollow point” bullets prohibited in 1907 Hague Convention IV, Article 23(e) as causing “superfluous injury.” When the open-tip rounds became available, Hays conducted an Article 36 review, and the M118LR rounds (as they are referred to) were approved for Special Operations personnel and snipers of all service branches.

Despite Article 36 approval, confusion about the legality of open-tip rounds persisted. For example, in 2006, a U.S. sniper drawing ammunition at a distribution point in Iraq asked for several boxes of M118LR. The ammo tech, noticing the open tip, refused to issue the ammunition. The issue was cleared up in less than a day when Hays’s Article 36 review was relayed to the command in Iraq. Nevertheless, the incident illustrates how misinformation prevailed even after Hays’s Article 36 review authorized the use of M118LRs.

Meanwhile, U.S. Special Ops personnel and military snipers everywhere were aware of Hays’s enduring efforts to get them LOAC-compliant specialized weaponry. They honored him with recognition and awards. He was particularly proud of the Special Operations Command’s 2001 Outstanding Civilian Service Medal. It helped that Hays was himself a shooter who participated in high power service rifle matches into his seventies. His shooter’s expertise in a wide range of military ammunition was gained the hard way, on Quantico’s 600-yard range, as much as through textbook study.

DoD Office of the General Counsel

In August 2003, when Hays’s tenure with the Army’s JAG Corps ended, he segued to the International Affairs Division of DoD’s Office of the General Counsel and, later, its Law of War Working Group. Hays was still in the thick of the law of armed conflict’s advancement.

It was during his tenure in the Office of the General Counsel, in May 2010, that he appeared as a speaker at a Dallas, Texas armaments conference. He recalled another conference he had attended some twenty years earlier at which a delegate had addressed the National Defense Industrial Association on the ballistics of military small arms ammunition. The representative argued that those ballistics were “inconsistent” with the law of armed conflict. Hays, never known for subtlety, was the next speaker. He began his remarks by saying, “Disregard everything this man just said.” He then outlined the DoD’s weapons review program, arguing that it was not only one of the oldest but also arguably the most comprehensive program of its kind. Hays’s commitment to providing U.S. combatant access to the most effective weapons available within the law of armed conflict was total. Anyone who interfered with that goal would need to be prepared to argue on the basis of facts rather than national political interests or personal profit.

A New Manual on the Law of War

Department of the Army Field Manual (FM) 27-10, The Law of Land Warfare, was issued in 1956. The manual’s genesis dated back to the 1863 Lieber Code. After Vietnam, proxy armed conflicts, and the 1977 Additional Protocols, FM 27-10 was recognized as outdated and no longer reflective of current law of armed conflict mandates. Something new was needed, and Hays Parks was at the forefront of the push for a new manual. I don’t recall when he first started talking about it, but the need for a new manual was a serious discussion point in the early 1990s. When the Department of Defense took an active interest in updating FM 27-10, Hays was the logical choice to take the lead in drafting it. Indeed, Hays formed and led a DoD Working Group that, in 2010, completed a multi-year “final draft” of a new U.S. law of war manual, largely the result of years of Hays’s knowledge, leadership, and dedication.

With the new manual complete—but for interagency reviews—Hays Parks retired in October 2010. He was seventy years old. After forty-one years of combined military and federal service, he had earned it. He had spent almost as much time as an adjunct professor of law, first at George Washington University’s School of Law, then at American University’s Washington School of Law. After so long as a student, practitioner, advocate, and guide, he finally would have the time to write his small-arms ballistics book.

But a twist of bureaucratic fate altered much of the work of Hays and his Working Group. The text was materially revised by a new group assembled by the General Counsel of the Department of Defense. The new Department of Defense Law of War Manual would not be published until nearly five years later, in June 2015, with no mention of W. Hays Parks in the Preface. When I raised the subject at one of the lunches for which we periodically met, he would not discuss it. His disappointment clearly ran deep.

Meanwhile, Hays continued to work on his ballistics book. At our last lunch, in early 2021, Hays railed at the U.K. publisher with whom he had contracted to publish the book. Hays had completed several hundred pages with more regard to content than speed. The publisher was pressing for an estimated completion date. Hays was angry. He was going to write his publisher a letter, he said, telling him that complex books like his take time, dammit!

I smiled to myself. Still crazy after all these years.


Gary Solis is a retired U.S. Marine (26 years active duty), twice serving in Vietnam as a platoon and company commander. After Vietnam he earned his J.D. from the University of California, Davis, and was a Marine judge advocate for 17 years. He is also a retired Professor of Law.



[1] Lt. Col. G.D. Solis, Marines and Military Law in Vietnam (Washington DC: GPO, 1989), 161.