What are all the causes of violence?

People.

Badly fitting underwear.

cheese and okra

Someone, somewhere, might have something better or different.

Hatred, greed, the love of money.

Because someone wants to take something from another, or because someone believes someone has taken something from them.

Bsically Tom it's failure to ed. the kids at an early age, before they reach teen and it's too late

The United States of America.

Human nature.

Wanting reality to be different than it is.

Human nature most often puts controls on these purveyors of violence, except, by and large for the USA. No country comes close to the US since WWII for illegal invasions and terrorism.

No country comes close to being war mongers in the fashion of the US. The US stands at 90+ percent of its years as a "nation" in a state of war, which really means, trying to control other countries so that the US can steal their wealth.

Hey JTT, how you doing? Where have you been hiding?

People wanting or taking something that they don't have.

Competition

Is camlok the renowned JTT of A2K? Well, his view really goes along with that of JTT.

How can nations be ended without violence?

This is actually a good question to consider, despite the flippant answers it's received.

On the one hand the answer can be Legion, but on the other it should focus on us as social animals.

Violence is an elemental force or life.

Hawks kill and first devour the internal organs of cute bunnies.

Wolves drag down and eat alive noble elk.

Preying Mantis females eat the heads of their suitors immediately after copulation.

On and on and on and on.

Nature is violent both terrestrially and extra-terrestrially

The Universe is violent.

Any notion that "civilized" humans shy away from violence is pure nonsense.

Humans are personally and culturally attracted to violence.

Despite the fact that we all, rationally, know that War is horrific, not only do wars continue, there is never a shortage of the humans willing to fight in them.

For centuries now artists and authors have attempted to present war in it's most realistically hellish reality and yet wars continue.

Spartans, Vikings, Mongols, Jannisaries, Mamalukes, Crusaders et al were all first hand witnesses to the horrific violence of war and yet they kept coming back for more, and more, and more.

Violence calls to us.

You do understand what "That's a real stretch" means, don't you, Finn?

Humans, that would be the USA largely, determined what the legal/moral considerations can be for countries to "go to war". These are to be found in the Nuremberg/Tokyo War Crimes Tribunals.

There were no provisions for "humans channeling their wolf/hawk/eagle ancestors".

Illegal invasions are war crimes - period. The USA has illegally invaded over 70 times since WWII, it has therefor committed myriad war crimes, not only for the initial illegal act but because all the evil that follows from that first paramount war crime is encompassed within it.

Better question: Why do certain nations have to use their incredible military power in a manner that is the equivalent of Mafia gangs seeking to enrich themselves off the poor rather than in the fashion that they constantly, lyingly brag about - we're a force for good, we bring democracy and freedom, we ... .