Restructure society to value cooperatation over competition.

Break down unjustifiable hierarchies where possible and reasonable. The flatter the power structure is without sacrificing much in the way of efficiency, the better.

The complete extinction of the human race

Rename armed conflict to something like “special military operations”

Kill everyone. No people, no wars! Win/win in my book

This is something my old history teacher once mentioned: we have games like COD and other esports titles. Just have all conflicts resolved via virtual combat instead of in real world violence

Make everyone bulletproof and bombproof. If it is no longer possible to kill people using weapons of war, then there will no longer be a point to fighting the wars. Either that, or things will escalate to a point where it is no longer sustainable to fight wars that way, also solving it. Mind control, or gelatinising everyone into a singular hivemind is also an option.

Somewhat more realistically, I think that exchanges and the internet are the ways to go when it comes to ending wars. It’s a lot harder to fight wars when you can empathise with the other side, and see them as your peers. It’s one of the reasons why soldiers who took part in the Christmas Armistice were shuffled around, since they became friendly during the ceasefire, and would be less wanting to fire weapons on the friends that they made.

A lot of wars tend to centre around dehumnaising the other side, and treating them as the “enemy”. Allowing people to co-operate and communicate mutually makes it a lot harder for that to take place, since you have experience with the “enemy”, they’re not that bad. You’ve even got friends there, and training a gun on them with the expectation and desire to turn them into a corpse is just not on.

Mass extinction event. Breed out aggression from our species we seem to be doing that but slowly. Space mining could potentially stop us from having war in Earth at least. AI takeover have everyone live on their own virtual reality paradise. For the most reasonable I think the best way to end wars is education and uplifting poverty nations not exploit them.

Edit: Or we can just be like Switzerland be a direct democracy, with how slow they decide things it will be highly unlikely to go to war at all.

There is this dystopia anime series called From the New World. The premise is a portion of humanity gained psychic power and led to the collapse of society because it’s so powerful that order could not be enforced. Far into the future there’s a cluster of communities that’s able to exist, and the way they went about it was to genetically engineered humans so when they harm another human it triggers body functions that make it harder for them to breath and other things. Killing another human also kills the aggressor. It kind of works on the interpretative level so it’s possible that using drones could still have an effect, probably.

Even in the story they explored ways to circumvent it though, but that’s kind of a tangent.

Impossible. There is 1-5% of the population who are born anti-social. It’s very difficult to socialise them, and some never do. They are vastly overrepresented in prisons. These people sometimes get into positions of power. Particularly in societies which value authoritarianism, like Russia and China. This cannot be helped. Instead, we must mitigate the effects of their reach. NATO, for example, is an excellent way to stymy these dictators.

A single world spanning country.

If we don’t kill ourselves off first it will probably happen eventually. Country sized used to be limited by things like communication latency, and the time it took to move forces around. Technology has shrunk the world so that those things no longer matter. The natural size limit on a country is almost certainly as large as the earth now.

It won’t happen soon, cultures will take time to become similar enough to merge. Leadership structures take time to be absorbed into a greater one (EU style) or have to forcefully taken over (Chechnya style, thankfully very rare these days). But with no real impediment to countries growing larger, it will happen eventually. With no-one able to fund or support rebellion and modern technology making police actions extremely effective it may well last effectively forever.

Whether it’s a democratic utopia, a dictatorial nightmare, or something in between for the common citizen is not yet defined. Either way, war, as in peer to peer conflict between sovereigns, will be over.

Let’s first address all the “nature” and “biological” not-really-true claims.

The Batek people of Malaysia are so averse of killing other humans that refuse to do it even when threatened with slavery https://peacefulsocieties.uncg.edu/societies/batek/

So, war is cultural, not biological.

Second, why do we do war?

At first glance, is for scarce resources, for survival.

But look at the modern wars. Are they for survival? Are they for resources that we need to survive?
No they are not.
They are for power.

But whose power?
The power of those who actually have to fight and die?
Certainly not.

The power of the rulers, who are greedy for more power.

Most people need to be scared into going to war, need to be convinced that they are defending their families and their “people”.

This is why rulers work very hard to build national identities, the good “us” vs the evil “them”.

Here we need three things:

1. We need a culture that knows how to recognize those greedy for power, those with a desire to dominate, and see them as the threat to freedom that they are, ie some sort of https://en.wikipedia.org/wiki/Leveling_mechanism
   There are several cultures that do that, but it has to be a deliberate and conscious thing.

2. We need to rethink our identities, national and not, because those identities are used to define the “other” that is ok to harm and kill.
   A way to do this is to make sure that people who want to travel and visit other groups can do so easily: this will help the various groups understand and humanize each other.

3. We need a culture that stresses the importance of non-violent conflict resolution.
   Because if all you know is violence, then that’s what you will use.

I mean, easier said than done of course, but I think that knowing the direction makes it easier to reach it.

For further reading on the subject, I would recommend Bob Altemeyer’s “The Authoritarians” and Graeber & Wengrow’s “The Dawn of Everything” from the top of my head.

Democracies rarely go to war with each other. Add mutual economical dependency to that and you have a strong base to avoid armed conflict. The EU is a good example for that.

Kill all humans

Universal basic income, universal food and shelter and education.

How about massive free psychedelic doses?