On Jus in Bello
Hi friends,
This is the second part of our series on the law of war. If you missed the first part of the series, on jus ad bellum, you can find it here.
As a quick refresher, under international law, the law of war includes two main categories: the law governing the decision to enter into armed conflict, or jus ad bellum, and the law governing the conduct of the participants within an armed conflict, or jus in bello (also sometimes referred to as international humanitarian law, or IHL).
This topic, unfortunately, continues to be timely: when I started this series, I had in mind by way of background the U.S. strikes on boats in the Pacific and the Caribbean Sea, as well as its military action in Venezuela. Since then, the U.S. and Israel have begun conducting military strikes on Iran, and Iran has retaliated in a conflict that is now spilling over into the entire region. And as this war unfolds, Trump administration officials keep making statements calling for “maximum lethality,” promising that “no quarter” will be given, and threatening to bomb civilian infrastructure, all of which are implicated by the framework we’re going to be covering today.
Jus ad bellum and jus in bello: why does the distinction matter?
With the caveat that, as with many areas of international law, the boundaries can sometimes get blurry, the short answer is that jus in bello applies regardless of whether the decision to go to war in the first place was a lawful one. In other words, even if one state commits an act of aggression in going to war against another state, both parties to the conflict are still bound by jus in bello as they conduct that war.
Or as the International Committee of the Red Cross (ICRC) puts it, “IHL is intended to protect war victims and their fundamental rights, no matter which party they belong to.”
What does jus in bello do?
At its most basic level, it does two things: it governs the methods used to conduct war, and the protections for those affected by war. These two categories are often referred to as “Hague Law” and “Geneva Law,” and they get their names from a series of international agreements on these topics negotiated in (you guessed it) The Hague and Geneva, respectively. (Though as the ICRC points out, this is a bit of a misnomer, because there is still some overlap between the two, including in the Additional Protocols to the Geneva Conventions.)
There are entire textbooks written on the laws that make up jus in bello (and some of them are sitting on my bookshelf as I write this—shout out to Documents on the Laws of War, by Adam Roberts and Richard Guelff), and today’s newsletter is…substantially shorter than that. But I want to equip you with some basics about what this area of the law is, how it’s developed, and where you can look for more resources if you want to learn more. I think it’s crucial to have an entry point into this material, even if it's a basic one, for reasons we’ll get into further below.
How we fight (Hague Law)
The Hague Conventions include instruments adopted at conferences in 1899 and 1907, as well as the 1954 Convention for the Protection of Cultural Property. There are a fair number of instruments here (which you can dig into on the ICRC’s website, if you have the time and inclination), but we can start with the 1899 Hague Convention with Respect to the Laws and Customs of War on Land. This Convention includes an Annex entitled, simply enough, Regulations Respecting the Laws and Customs of War on Land. The Regulations contain the foundational assertion that “the right of belligerents to adopt means of injuring the enemy is not unlimited” (art. 22), as well as a number of specific prohibitions on parties to hostilities, such as employing “poison or poisoned arms,” or “arms, projectiles, or materials of a nature to cause superfluous injury” (art. 23).
The 1899 Convention and Regulations were revised in 1907 (for example, “superfluous injury” was changed to “unnecessary suffering”), but contained many of the same provisions. Other instruments included in the Hague Conventions prohibit things like the laying of automatic contact submarine mines, the bombardment of undefended ports, and the use of expanding bullets.
There are many more specific examples of prohibited conduct that we could get into here, but instead I want to focus on one very important, and very deliberate, lack of specificity. Both the 1899 and 1907 Conventions contain language in the preamble, now referred to as the Martens Clause after the diplomat who negotiated it, that takes into account inevitable changes in weaponry and the conduct of hostilities as time goes on and provides that customary international law continues to apply to those changes. As written in the 1907 Convention, the Martens Clause states,
“Until a more complete code of the laws of war has been issued, the High Contracting Parties deem it expedient to declare that, in cases not included in the Regulations adopted by them, the inhabitants and the belligerents remain under the protection and the rule of the principles of the law of nations, as they result from the usages established among civilized peoples, from the laws of humanity, and the dictates of the public conscience.”
In a 1996 advisory opinion on the use or threat of nuclear weapons, the International Court of Justice stated that the Martens Clause “has proved to be an effective means of addressing the rapid evolution of military technology.”
Who we protect (Geneva Law)
The Geneva Conventions (also conveniently located on the ICRC website—I promise this newsletter is not an ad for the ICRC, I just think they’re great) include instruments from 1864, 1906, 1929, and what I think of as the “big four” Conventions from 1949, as well as Protocols to the Conventions adopted in 1977 and 2005.
The 1949 Conventions address:
(I) the Amelioration of the Conditions of the Wounded and Sick in Armed Forces;
(II) Wounded, Sick and Shipwrecked Members of Armed Forces at Sea;
(III) Prisoners of War; and
(IV) Civilians.
The titles of these Conventions give you a good idea of the specific populations they’re intended to protect, and go into detail on what obligations apply, and how they should be implemented.
The phrase “Common Article 3” may also sound familiar to you—this is an article found in all four of the Geneva Conventions discussed above, and which applies, on its face, to conflicts “not of an international character” occurring in one state’s territory (such as a conflict between a state and a breakaway group). But the International Court of Justice held, in a case involving the U.S. called “Military and Paramilitary Activities in and against Nicaragua,” that Common Article 3 constitutes a “minimum yardstick” of rules that apply to both international and non-international armed conflicts, in addition to the “more elaborate rules” that apply to international armed conflicts.
In other words, the provisions of Common Article 3 contain the bare minimum of protections that apply to armed conflicts, including its prohibitions on things like torture, murder, taking hostages, and humiliating and degrading treatment; and providing that the wounded and sick “shall be collected and cared for.”
Jus in bello in the news
I want to circle back now to a question I posed earlier: why do I think it’s worth it to give you what amounts to a CliffsNotes version of an extremely complex area of international law? And how is this relevant to your life, if you’re not a military officer or one of the lawyers, judges, and academics whose careers focus on these issues?
And the answer comes back to one of the main reasons I started this newsletter in the first place: because international law and foreign policy are not things that should be siloed off or inaccessible to the people they are designed to serve. I want you to be able to look at a headline in the news or on social media and be able to parse for yourself what the context is, what your concerns are, and what your leverage is to work for the world you want to see.
This is, unfortunately, especially critical when it comes to the way war is discussed in the media. A recent example is Secretary of Defense Pete Hegseth’s statement that the U.S. would “keep pushing, keep advancing. No quarter, no mercy for our enemies.”
Remember the Regulations Respecting the Laws and Customs of War on Land (truly just rolls off the tongue) discussed above? Art. 23 lists as one of its “especial[] prohibitions” the act of declaring “that no quarter will be given.” This language is echoed in Article 40 of Additional Protocol I to the Geneva Conventions, which states, “It is prohibited to order that there shall be no survivors, to threaten an adversary therewith or to conduct hostilities on this basis.”
Put more plainly, the statement that the U.S. will give no quarter to Iran is not just the Secretary of Defense’s particular brand of bluster and toxic masculinity. It’s a war crime.
And that is what I want to equip you to better understand as we follow the news together.
ICYMI
I’m grateful for the thoughtful people in this community, and all the things we’ve covered together in the last few weeks, including:
- A Special Edition of The Brief covering the launch of military strikes against Iran;
- Updates on the White House’s War Powers Report, self-defense claims, and mounting casualties;
- Updates on other issues we’ve been covering together, including tariff refunds and human rights violations in Hong Kong;
- An overview of the developing situation with Cuba, including the U.S. fuel blockade and threats to invade; and
- A discussion of election interference in Slovenia and Hungary.
If any of these topics interest you, and you’re not yet a paid supporter, you can sign up for a free 30-day trial period to access all paid content and see what you think. I can promise a read-through of our archive will feel more fulfilling than doomscrolling, though that's not a high bar these days.
And in the meantime, I’ll see you back here soon with next week’s edition of The Brief.
Alexis
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