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Program on International Law and Armed Conflict (PILAC)

Research guide for Harvard Law School's research program on international humanitarian law and the law of armed conflict.

PILAC Research Guide

Welcome and Introduction

This research guide for the Harvard Law School Program on International Law and Armed Conflict (PILAC) provides information about researching international humanitarian law (IHL) and the law of armed conflict (LOAC). 

Its intended audience is PILAC researchers and anyone else interested in IHL/LOAC research.

Research Librarian Jennifer Allison, who is the Harvard Law School Library's PILAC liaison, created and maintains this guide. Her contact information is at the top of the page. 

Below are links to more information about PILAC and its work.

Using HOLLIS: The Harvard Library Catalog

HOLLIS: Use and Strategy

Harvard's HOLLIS Library Catalog ( is the best way to find research materials in Harvard's libraries.  All PILAC researchers will need to use HOLLIS in their work for the program.

Using HOLLIS effectively takes some practice and strategy. This section of the guide describes a procedure for using HOLLIS that is based on the types of research projects that PILAC has undertaken in the past.


1.  Getting Started: Understand What You're Searching

HOLLIS has two search modes:

  • Library Catalog means searching for materials in the collections of Harvard's libraries: books, eBooks, periodicals (by periodical title, not article title), photographs, videos, print government documents, manuscript collections, and more.
  • Everything means, in addition to the library catalog, searching a large electronic index of materials called Primo that includes information about periodical articles and book chapters.  

If you type a term in the search box on the HOLLIS home page and press Enter, HOLLIS will do an Everything search by default.


2.  Searching: Start Broad

You will have more control over your search if you use HOLLIS's Advanced Search option.  Do this by clicking ADVANCED SEARCH at top of the home page. 

Start out by searching as broadly as possible for all of the materials that you might have access to that are related to PILAC's work, like this example:

Search for: Everything
Keywords anywhere + Contains + "law of war" OR "armed conflict" OR "international humanitarian law" OR "geneva conventions"


3.  Narrowing Your Search: Adding Keywords

Now, get to work narrowing down those results so that they are more tailored to what you want.  

Here are some options for adding more search terms to the original query, based on the nature of the research that you are doing.

  • Add a jurisdiction-specific keyword, accommodating spelling variations in nouns and adjectives
    (example: France OR French)
  • Add a keyword for the principle you are researching
    (examples: "state practice" or "domestic law" or "rules of engagement" or "jus ad bello" or "jus in bello" or "responsibility to protect" or "protection of civilians" or "proportionality") 
  • Add a keyword for a type of operation or conflict
    (examples: "asymmetric" or "international" or "non-international" or "extraterritorial" or "civil war" or "cyber" or "counter-terrorism" or "counterinsurgency" or "self defense" or "targeting" or "preemptive attack" or "humanitarian intervention")
  • Add a keyword for a type of weapon or instrument
    (examples: "drone" or "unmanned" or "autonomous" or "robot" or "landmine")  
  • Add a keyword for a humanitarian principle, objective, or action
    (examples: "just war" or "medical care" or "humanitarian aid")
  • Add a keyword representing an identity
    (examples: "soldier" or "combatant" or "civilian" or "non-state actor" or "belligerent" or "insurgent" or "armed group" or "mercenary")
  • Add a keyword for a specific treaty, convention, or agreement
    (examples: "non-proliferation of nuclear weapons" or "anti-personnel landmine convention" or "Rome Statute")
  • Add a keyword representing an international body
    (examples: "Security Council" or "NATO" or "International Committee of the Red Cross")
  • Add a keyword for a type of resource
    (examples: "research handbook" or "military manual" or "dataset")
  • If you want to focus on finding books in Harvard's libraries, add a relevant Library of Congress Subject Heading (LCSH) Keyword
    (examples: "armed conflict (war)" or "humanitarian law" or "war (international law)" or "military art and science")

Defining Key IHL and LOAC Terms

International Humanitarian Law (IHL)

International Humanitarian Law (IHL) creates legal restrictions on waging warfare for the purpose of protecting non-participants. It is comprised of international treaties and customary law.

Law of Armed Conflict (LOAC)

"Armed conflict" is the term used in international law to describe when a state uses its armed forces in connection with a dispute.  

The Max Planck Encyclopedia of Public International Law (MPEPIL) defines several important terms related to this concept. Links to those definitions, as well as other relevant resources, are listed below.

Jus ad Bellum and Jus in Bello

Basic definitions of these concepts are available in the Parry and Grant Encyclopaedic Dictionary of International Law:

  • Jus ad bellum: the "right to resort to war;" also, concept that "emphasize[s] the criteria for a legal or just war."
  • Jus in bello: the "corpus of the laws and customs of war."

In scholarly literature, jus ad bellum and jus in bello are often discussed together. They may be discussed under broader philosophical, religious, or moral principles using the terms just war theory or just war doctrine (jus bellum iustum). 

Sometimes these are discussed in combination with a third principle, jus post bellum, which encompasses post-conflict legal norms.

"Non-International" Armed Conflict (NIAC)

In general, an armed conflict is considered to be "non-international" in nature when the party on one side of the hostilities is comprised of non-state actors, such as terrorists or insurrectionists.

This classification is important because it triggers the rules of engagement outlined in the Geneva Conventions Additional Protocol II of 1977. The original Geneva Conventions of 1949 only govern an "international" armed conflict between two sovereign states.

"Asymmetric" Armed Conflict

If there is a significant difference in military strength, technical capabilities, and/or other elements between the two parties in an armed conflict, it is generally referred to as an "asymmetric" armed conflict.

Conduct of Hostilities

International law has specific rules for how warfare is to be conducted. Among the topics these rules cover include the protection of civilians, cultural property, and the environment.  There are also rules for conducting cyber operations. 

Changes to the nature of warfare over time have complicated the issue of whether and how civilians are engaged in armed conflicts. This issue is often referred to in the IHL literature as "direct participation in hostilities" and it comes up often in PILAC research.

Protection of Civilians (POC)

According to the ICRC, the protection of civilians during armed conflict is a "cornerstone" of IHL. This includes not subjecting them to violence, but also to ensure that their access to food, water, housing, and medical care is not disrupted.

Responsibility to Protect (R2P or RtoP)

The United Nations established its Office on Genocide Prevention and the Responsibility to Protect in 2005. This office is home to two special advisors: one on the prevention of genocide and the other on the responsibility to protect. They are tasked with "advanc[ing] national and international efforts to protect populations from genocide, war crimes, ethnic cleansing and crimes against humanity (atrocity crimes), as well as their incitement."

Books for Starting Your Research

Selected Foundational Books on IHL/LOAC

ICRC IHL Bibliography

Additional Research Materials

Journal Directories

To find additional journals not listed in this guide, try searching these journal directories.

Book Series

Some publishers offer series of works that discuss topics relevant to war, armed conflict, and international humanitarian law research.  Click a series link below to view a list of the series titles in the Harvard Library collections.


Masters theses and PhD dissertations provide book-length information on topics of interest to PILAC and bibliographies of relevant research materials. 

State Manuals

Manuals on the law of armed conflict serve two purposes: (1) establishing "an agreed version on the law of armed conflict" and (2) setting forth "state practice relating to the law of armed conflict."

(Source: Earle A. Partington, Manuals on the Law of Armed Conflict, Max Planck Encyclopedia of Public International Law (2016), 

The US Naval War College's Stockton e-Portal includes links to armed conflict manuals from many jurisdiction on its manuals page:

The ICRC also maintains a list of state manuals at

Examples: Using Data for IHL/LOAC Research Projects

United Nations Research

Treaty Research

Treaty Materials

Travaux Préparatoires

The documentary history of the preparation of an international agreement is generally known as its Travaux Préparatoires. The resources below can be helpful in finding these materials for international treaties and agreements.

Geneva Conventions Materials

"The Geneva Conventions and their Additional Protocols form the core of international humanitarian law, which regulates the conduct of armed conflict and seeks to limit its effects. They protect people not taking part in hostilities and those who are no longer doing so." (ICRC)

IHL/LOAC Scholars and Organizations

Selected IHL/LOAC Scholars

Below is a list of scholars and academics who teach and research IHL and armed conflict law.  Links to websites with biographical information and, when available, bibliographies are provided.

Institutes, Programs, and Organizations

Other Research Guides

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