If not all, the vast majority of wars in known history were dirty, cruel and with a lot of civilian casualties. That makes me wonder if there has ever been a "clean" war where both sides played "by the rules"? The criteria would be:

  • Minimal civilian causalities
  • The war started with a declaration of war
  • No illegal weapons (biological, chemical etc.) used
  • The war ended with a treaty
  • No or minimal propaganda was used
  • The two sides have similar stands on the reasons why the war started
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    I don't know why this is getting downvoted. The question has a clear definition for what it considers a "clean" war.
    – Schwern
    Oct 22, 2015 at 0:33
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    I don't know a lot about it, but maybe the Falkland Islands?
    – Golden Cuy
    Oct 22, 2015 at 7:43
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    This is what I picture it would be like if Canada went to war.
    – IQAndreas
    Oct 22, 2015 at 8:27
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    @Schwern Perhaps it's the title of the question "What was the most clean..." leaves room for "opinion-based answers". I think a better title might be "Has there ever been a "clean" war?" (which fits well with what the asker is actually trying to find out).
    – IQAndreas
    Oct 22, 2015 at 8:40
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    "illegal weapons" is in itself wrong. There's no international law, just treaties that countries sign on to... And those treaties didn't exist in the past, so those weapons weren't "illegal" either. Declarations of war were also not common (and tbh they still aren't) until recently. Propaganda is "dirty"? Makes no sense. Etc. etc. etc.
    – jwenting
    Oct 22, 2015 at 20:19

11 Answers 11


The Anglo-Swedish war of 1810-1812. A phoney war forced upon Sweden after the devastating defeat in the Finnish war; neither side wanted to fight the other, and no battles were fought. There were, however, a formal declaration of war and a signed peace, and British troops that were stationed at the Island of Hanö occupied it during the war.

  • 4
    Personally I find it controversial whether this is really a war, as no act of war appeared during the conflict.
    – Bregalad
    Oct 22, 2015 at 16:04
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    @Bregalad It doesn't matter if there were any "acts of war", rather, it matters if a declaration of war was made (and it indeed was). In fact, simply formally declaring war is in itself, an act of war.
    – SnakeDoc
    Oct 22, 2015 at 16:30
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    It's certainly a war, since war was declared. But it's arguably not "a war that was ever fought." :-P Oct 24, 2015 at 13:13
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    A war where nobody fought: either Sun Tzu's acme or "not a war" in the first place. interesting puzzle to try and sort out. Jun 25, 2017 at 2:26

The Anglo-Zanzibar War fits your criterion, in part because it was so short, but it was also conducted with civil restraint. The new Sultan was suspected of assassination and violated a British treaty by occupying the palace. The British attempted negotiations and finally issued an ultimatum to vacate the palace at 0900. Half an hour before a final attempt at negotiation was attempted and the British made it clear they would open fire.

The palace grounds were fired upon. A single Zanzibar naval vessel was sunk when it fired at the British fleet. Surrender was accepted 38 minutes later. The British landed troops to help put out the fire and patrol the streets. The sultan fled to the German consulate who escorted him out of the country.

About 500 people were killed in the bombardment and subsequent fire. It's difficult to know who was civilian and who was not; the palace was defended, in part, by a hastily raised militia. The British gave ample warning of their intent to fire for them to have been evacuated.

The First Barbary War between the United States and the Barbary pirates matches your criterion. The cause was clear: Tripoli demanded their traditional protection money from the US and the US refused to pay. Tripoli declared war on the US by chopping down the flag in front of the US consulate (according to Wikipedia, this is traditional). The US Congress did not formally declare war, but ordered that armed American vessels were to to seize all vessels and goods of the Pasha of Tripoli "and also to cause to be done all such other acts of precaution or hostility as the state of war will justify." Tripoli harbor was blockaded by a multinational force and raids were conducted against their fleet.

After years of blockades and raids, a US mercenary force approached Tripoli by land via Derne. The US commander requested safe passage and supplies. The city governor refused, reportedly with "My head or yours!". The American's target was a fort and the governor's palace. I have no mention of civilian casualties, but city battles are never pretty, and mercenaries aren't the best behaved.

Soon after the capture of Derne, with Tripoli threatened and the blockade being bad for business, the pasha surrendered. A treaty was signed declaring a "inviolable and universal peace, and a sincere friendship", exchanging all prisoners, ending the blockade, and withdrawing from Derne. Curiously, after refusing to pay tribute, the US agreed to pay ransom for American prisoners.

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    It amuses me that after the Anglo-Zanzibar war, the losers were made to pay for the shells that the British ships had fired. That really underlines how one-sided and pointless the 'war' was, it almost seems like a training exercise.
    – Steve Bird
    Oct 22, 2015 at 6:11
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    @SteveBird I would say that reparations of war usually are that one sided. The difference with more lasting wars is that in those reparations of war cover a lot of expenses that are difficult to calculate, while in the Anglo-Zanzibar war it was evident that the UK had suffered no damage at all so they could only claim the ammo spent.
    – SJuan76
    Oct 22, 2015 at 16:33
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    So, what was so clean about these conflicts? -1, I am afraid Jun 24, 2017 at 20:55
  • @FelixGoldberg They match the OP's criteria. The question isn't about what is a "clean war", they defined that for our purposes the question.
    – Schwern
    Jun 24, 2017 at 20:59

The Slovenian war of independence, which was fought in 1991 was pretty clean by your standards.

Civilian casualties are stated as 12 foreigners who strayed into the line of fire, and there were also a few Slovenian civilian casualties. But combined these were much less than the 63 military casualties. The Yugoslav army destroyed some civilian property, such as parts of an airport and some passenger planes on the ground, and they also targeted TV transmitters. After ten days of fighting, a cease-fire was declared and the Yugoslav army retreated to Croatia, where a much bigger war was brewing.

There was no official declaration of war, but by declaring independence, the Slovenian authorities knew what would follow and were prepared.

No illegal weapons were used.

The war ended with a treaty.

All propaganda was kept at normal levels.

the two sides agree that the cause of the war was Yugoslavia's unwillingness to let Slovenia declare independence.

  • 1
    The Slovenian war of independence especially sticks out, if think of the fate of the other parts of ex-Yugoslavia.
    – Dohn Joe
    May 20, 2020 at 7:53

How about Flower Wars, between the Aztec and their enemies? These were conducted according to very strict conventions. There were limited combatants and the location was preselected. The aim was to gain sacrificial victims, and early in the wars casualties were low (they got higher as the war went on, though). Much of the violence was the sacrifice (later) of prisoners and not from the battle itself.

  • Didn't know about it. It seems to be a really good example. However, in discussion section, Wikipedia says "The flower wars were not what we would consider a 'war' by today's standards." Oct 22, 2015 at 0:16
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    except for the later sacrifices, wouldn't this look more like a medieval jousting tournament, which was heavily regulated and casualties were rare?
    – vsz
    Oct 22, 2015 at 13:29
  • en.wikipedia.org/wiki/Mamankam_festival where Chaver(suicide squad) were used to challenge the ruler and his soldiers in a predetermined place and time. Oct 22, 2015 at 14:53
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    Sorry, -1. They ripped out the losers' hearts. How's that clean? Jun 24, 2017 at 20:58
  • @FelixGoldberg I guess because the human sacrifices weren't technically part of the war but conducted afterwards. Technicality, but then the entire question is about technicalities.
    – jwenting
    Jun 26, 2017 at 6:29

I'd name the Sonderbund War in 1848 in Switzerland. The catholic Swiss cantons attacked the protestant Swiss cantons because they wanted to separate.

However, three weeks after it broke out, the cantons of Fribourg and Lucerne was successfully defeated by governmental forces and the other catholic cantons didn't want to continue to rebel. The war ended with a peace treaty that consolidated the country as a single country instead of a federation of independent states. The war did exactly 93 victims.

There was also the Falklands War in 1983 in Falklands islands, opposing UK and Argentina. Some soldiers died, even horribly; However the war was short, and on both sides there was not really hatred for the enemy but rather the obligation to obey to their respective government and conquer the island. The war was too short to escalate into something really messy like it usually does, with a spiral of torture, hatred, harm to civilians, etc...

This war meets pretty much all standards for "cleanness" given by the OP. There was 3 civilian victims and 904 military victims.

  • About the Falkland wars, you might want to had the numerous traumatisms caused by the war among the troops. I read that about 200 British airborne soldiers suicided themselves. And those troops suffered as well about 200 casualties. So you might want to add to effective combat losses the post-fight losses and the numerous traumatisms that did not led to actual deaths (Prince Andrew for example spoke about a traumatism that forbid him to sweet) Dec 15, 2019 at 17:22
  • Later study does not seem to bear out this statistical claim regarding suicides amongst Falklands veterans. See bbc.com/news/uk-22523317 and researchgate.net/publication/…
    – R Leonard
    May 25, 2020 at 14:05
  • And even if studies had detected some suicides or other war sequels, that is likely to mean that in that war sequels had been more studied than in all previous wars, not that the Falklands War wasn't more "clean" than them.
    – Pere
    Oct 29, 2021 at 20:45

I will add to the list the Toledo War. Both Michigan and Ohio raised militias with the intent to defend their respective claim to the Toledo strip. Shots were fired, although these were later claimed to be just warning shots over the heads of those who were already retreating. Apparently there was exactly one casualty: a stab from a pocket knife, resulting in a non-life-threatening wound. The conflict ended with a concession where Ohio got Toledo and Michigan got its upper peninsula.

About the only one of your criteria this war does not meet was the lack of propaganda. Both sides passed "laws" forbidding residents of the strip from paying taxes to the other, spread rumors about the strength and abilities of its militia, and so on. Mostly it was political blustering.

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    One drawback of this candidate is that US states aren't allowed to make war against each other, the whole thing was probably highly illegal.
    – Schwern
    Oct 24, 2015 at 19:04
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    There is truth to @Schwern's comment, but to play devil's advocate: 1. Allowed or not, the Civil War happened. 2. Michigan was not a state at the time (was a territory petitioning for statehood). 3. The OP did not require that the war itself be legal, merely that the weapon types be legal.
    – cobaltduck
    Oct 25, 2015 at 17:07

The Dutch - Scilly Islands War or The 305-Year War comes to mind.

  • zero civilian casualties
  • started with a declaration of war
  • no illegal weapons were used
  • Ended with a treaty signed on 17 April 1986, 305 years exactly after beginning of hostilities.
  • No propaganda was used - a reason why this war lasted that long; everybody had forgotten it!
  • Hm, it's alleged war and it's very existence is disputed. It sounds like Montenegro-Japanese "war" which lasted for almost a century. May 20, 2020 at 23:11

I think that the "Cabinet Wars" of the 18th century might fit in here.

[A]lso known as "war between princes." Such wars involved small armies, noble officer corps, limited war goals, and frequently changing coalitions among the belligerents.

As an example:

Berlin was not plundered during the Seven Years' War of 1756-1762, despite having fallen into enemy hands not once but twice.

  • 1
    If the "Cabinet Wars" include the War of Spanish Succession and the other wars stated in the Wikipedia article the answer linked, they weren't clean at all.
    – Pere
    Sep 23, 2017 at 18:01

I think the answer to this question is the Parsley/Perejil island conflict between Spain and Morocco in 2002 https://en.wikipedia.org/wiki/Perejil_Island_crisis.

Morocco occupied with an invasion force of 12 men an uninhabited island that Spain considered theirs. A week later Spanish special forces landed on the island and took the Moroccans prison without firing a shot. The prisoners were released and returned to Morocco the same day.

No deaths, no wounded, not even a shot fired.


The cleanest war was probably the Cold War... because it was never fought.

There were casualties - the Soviets shot down quite a few US spy planes, and that was kept very quiet. And there were proxy wars, such as Korea and Vietnam, but overall, the Cold War was marked by an absence of armed conflict, avoiding the huge casualties and destruction of cities that normally come with a war.

In the end the Cold War was an economic war. And the western nations won it the capitalist way - they outspent the Soviets. Kruschev once famously said that when the time came to hang the western leaders, they would sell him the rope.

Unfortunately for him, he couldn't afford to buy it.

  • 2
    But what about the proxy wars the Cold War engendered? Few of them were even remotely clean. Jun 24, 2017 at 20:59
  • True, but they were tiny in comparison to the destruction that a USSR/NATO conflict would have yielded. The cleanest war is the one that is not fought at all.
    – tj1000
    Jun 24, 2017 at 21:02
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    Does not meet the criteria established in the question.
    – justCal
    Jun 25, 2017 at 0:32
  • The cold war was never formally declared, as it was not technically a war at all. It was an undeclared conflict fought with mass propaganda as well as high levels of "clandestine" intelligence/spy operations, including assassinations of key people on the other side using means definitely illegal in the countries the assassinations were carried out.
    – jwenting
    Jun 26, 2017 at 6:33
  • When was the last formally declared war? The concept has become all but obsolete. If you want to take the narrow definition of a formally declared war, then the answer will have little meaning today. The cleanest conflict is the one that was never fought.
    – tj1000
    Jun 26, 2017 at 13:32

I'd nominate the Western Front of World War I.

The conflict largely involved non-asymmetrical war between two sides.


Minimal civilian casualties: civilians were killed from the sinking of boats in the Atlantic - possibly ones that were carrying munitions. Also, Entente forces blockaded Germany, affecting its ability to import food. Away from the Western front, Turkey committed genocide, but I'm focusing on the Western front.

The war started with a declaration of war: yes.

No WMDs: Germany used chemical weapons.

The War ended with a treaty: The Treaty of Versailles.

No propaganda: there was a lot of persuasion, but I'm not aware of large-scale, sustained efforts at deception.

Parties can agree on the cause: I think so. Hostile military alliances.

Considering how many people died in WWI, I'm of the opinion that "cleanness", while measureable, isn't a very useful metric.

  • 4
    The western front is not a war, WWI is.
    – Jeroen K
    Oct 22, 2015 at 8:32
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    @JeroenK Of course, one could also argue that WWI can be categorized as a collection of wars, often, but not always, interconnected.
    – IQAndreas
    Oct 22, 2015 at 8:46
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    I disagree, these different conflicts are called theaters, for them to be separate wars they'd have to have a different declaration of war, different belligerents or different reasons and different peace treaties. In addition to that you're wrong when you state no civilian casualties happened on the Western front, just take a look at Belgium.
    – Jeroen K
    Oct 22, 2015 at 8:52
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    The Western Front covered a miles wide swath of Europe from the North Sea to Switzerland destroying the lives of the people who lived there. Poison gas caused at least 100K civilian causalities. Much of the fighting happened in neutral Belgium culminating in the Rape Of Belgium. The French mutinied. Propaganda was rampant. The Treaty of Versailles was humiliating.
    – Schwern
    Oct 22, 2015 at 16:58
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    "Minimal civilians casualties". You've obviously never been to Ypres salient (or the surrounding areas). Every village (no matter how small) has a statue for the civilians who died during WW1 ....
    – User999999
    Jun 23, 2017 at 6:46

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