Criteria for a Just War

Military action shouldn’t be taken unless it meets all the criteria for a just war; non-violence is preferable but not always appropriate.

Many people are instinctively pacifist; they feel empathy for the people who get killed, wounded, or displaced by war.  Pacifists can also argue that war degrades those who rely upon it as an instrument of policy – constraining their own basic freedoms in the name of security and, during the Cold War for example, leading them to choose allies whose governments would otherwise be thought of as insupportable.  For example, in 1955 a Quaker paper entitled Speak Truth to Power criticised the way in which America’s Cold War policies reduced its moral standing in the world and threatened freedoms within its own society:

“Since 1945 there has been a steady erosion of the values that were formerly considered the very foundation stones of American democracy.  Proceeding from the false assumption that whatever is anti-communist is therefore democratic, many Americans have supported or acquiesced in measures that have generally been considered central characteristics of totalitarianism: spying on fellow citizens; anonymous denunciations; restrictions on freedom of movement, speech, and press; prosecution for beliefs rather than acts; the reversal of the traditional presumption of innocence until proof of guilt; the gradual militarization of our minds and our society; and the growing confusion of our thought and language until we no longer feel any astonishment at the use of a phrase like “the free world” to include all nations, however dictatorial, and colonies, however exploited, that are not under Soviet control.”

This paper was remarkably prescient: the gradual loss of civil liberties in America persisted up to and including the era of George W Bush, and America’s moral authority in the world declined catastrophically.  Although the paper was primarily concerned with America’s position, its arguments can be assumed to apply equally to any other power with militarist policies.  The loss of moral authority within the Soviet Union was arguably a major factor in its collapse.

Many people judge each situation on its merits.  They might support a war on the grounds that it would be morally better than alternative policies.  The Internet Encyclopedia of Philosophy entry on Just War Theory records a long history of writing on the subject, from Thomas Aquinas onwards.  Robert Skidelsky’s article, The just war tradition, included a historical overview, a definition with clarification, a review of the role of the UN and a brief survey of contemporary issues to which the theory might be applied; it described ‘just war theory’ in these terms:

“Today, a rich and sophisticated discussion over centuries is usually presented as a list of propositions covering three topics – jus ad bellum, jus in bello and jus ad pacem.  The first aims to determine whether a war is justly started, the second is concerned with the just conduct of the war, and the third – and most shadowy – explores the conditions of a just peace.  The propositions support each other, like bricks in an arch.  …

The requirements for a just war are traditionally reduced to six: just cause, legitimate authority, last resort, proportionality between offence and response, reasonable chance of success and right intention.”

In the terminology of this book, these requirements belong to different dimensions of power:

●  “Just cause”, “proportionality”, and “right intention” appear to be moral criteria. People’s assessments will depend on their beliefs.

●  “Legitimate authority” is a legal criterion.

●  “Last resort” is a judgement as to whether both legal and political means have been exhausted.

●  “Reasonable chance of success” appears to be mostly a military judgement, which is classified as Ungoverned Power in this book because it lies outside the four dimensions of structured governance. The question of whether a lasting peace can be achieved, though, also requires a political assessment.

As Skidelsky commented, the propositions of ‘just war theory’ “support each other, like bricks in an arch”.  No-one will accept that a war is ‘just’ unless they think that all the criteria are satisfied, though most people will rely upon the advice of others in the legal, political and military aspects.  The application of ‘just war theory’ was changed by the establishment of the UN, and it has to evolve further as a result of changes in the military environment, as examined in later chapters:

●  A humanitarian intervention to prevent genocide might be thought to be both a “just cause” and “right intention”, for example, but this should now be subject to a collective assessment by the UN Security Council – which is the only source of “legitimate authority” to use military force ( Several countries might then contribute to the use of force, or lend other forms of assistance, as was the case with driving Saddam Hussein out of Kuwait in what the BBC described as Operation Desert Storm: Last of its kind.

●  Legality alone, though, does not make an action prudent or beneficial to those affected. Chase Madar wrote, in an article Libyan War: Legal, Multilateral, and Still Wrong, that “[w]hatever value we attach to legality, it is never a proxy or substitute for prudence, good sense or morality”.  The Libyan intervention turned into a disaster (

●  “Last resort” depends upon whether the matter had been submitted to an international court (, whose rulings might also be seen as validating some types of “just cause”.

●  “Proportionality”, which can be taken as requiring a minimum loss of life in achieving the objective, has become more complicated when wars are conducted where civilians are living and not on a remote battlefield (

●  A “reasonable chance of success” can be evaluated by examining the utility of military force (7.4.1), but its political viability must also be considered: ‘realpolitik’ (

●  The Geneva Conventions cover jus in bello, legally prohibiting avoidable harm to non-combatants (

●  The requirements for a just peace, jus ad pacem, include ensuring that the defeated party accepts the result, which depends upon some form of reconciliation. The establishment of the European Union after the Second World War was an outstanding example of reconciliation that was achieved by political negotiation and which accorded dignity to both sides (6.6.5).  In the absence of reconciliation, an imposed settlement merely suppresses the confrontation until the balance of power changes again (7.4.5).

For this chapter, the question is whether people as individual moral agents are persuaded that a war is ‘just’ and what kind of influence they can bring to bear on politicians.  If people think that a proposed war would be unjust they can put pressure on their politicians by demonstrating to try to prevent it, as they did in 2002 in what the BBC described as a ‘Million’ march against Iraq war, although the politicians ignored them on that occasion.  People’s political support, or lack of it, ultimately limits the use of war as an instrument of policy (6.3.6).

People can also react against misbehaviour and atrocities in the conduct of a war, as reported for example in a BBC article: Picture power: Vietnam napalm attack, which showed a photograph of a little girl running away from a US chemical weapon attack.  The anti-war protest movement gathered momentum and politicians were unable to ignore it.  An estimated 2 million people went on what a BBC retrospective report described as 1969: Millions march in US Vietnam Moratorium.



This page is intended to form part of Edition 4 of the Patterns of Power series of books.  An archived copy of it is held at https://www.patternsofpower.org/edition04/4355a.htm.