I kind of thought that if WW1 didn't have the Americans running around with shot-guns, then it would have evolved into a 'Who can reach the farthest' kind of war. Rockets, Air Planes, Train-artillery, Espionage, Sabotage, Snipers, but very, very little in the way of actual trench-taking. And sometime soon after, Communist ideals would spark a revolution in two nations simultaneously and the entire thing would grind to a halt. The Anti-Comintern Pax (not 'Pact') lasts for a bit until the populations of all nations involved are subdued. So then they try it again, though who starts where I'm not so sure (I'm not a communist in Germany or France, but these two would be my big guesses for the simultaneous revolts) and the Colonies/Dominions revolt, becoming Socialist (at the very least) or Communist if their troops don't make it home in time (India, South Africa, Australia, Indochina, ones that are far, far away).
So, after the world is in open arms, Capitalist and Communist, then the United States begins to step in where it's not really wanted (It's kind of like "Who the hell invited you?") because of the isolationism not working out as well as they hoped. While everyone else is in these large alliances and neutral nations aren't people who had your back so they shouldn't be helped in return. Then the Socialist/Communist nations (a very small group) become a faction all their own and the two already-fighting sides can't shake loose their original conflict, their own home reels and the world's Communist nations. So the world kinda collapses into tinier states, ones around Province/City-State size that make alliances based on whether they're Communist, British-sided, German-sided, or trying to be neutral (and you can't be neutral when you're in flux about your own government). Soon enough it's such a mess people who have tried to stay on the fence are dragged under the surface of these turbulent waters if they're not strong enough.
By the time the world finally settles down, there are no real winners of World War One, it's a big mess and the people who came out on top are the United States. They're in no position to brag though, they're a technologically advanced state that can't decide whether or not to let Communists be recognized. By the time someone suggest a UN/LoN organization, the world is ready to say yes, but no one is sure who the voice belongs to anymore (Germany or Bavaria or Kaiser reich? France or Paris or the Army?). So the Global-Peace-Organization falls faster than OTL and soon a bigger war is happening with the Americans making a theoretical profit off of most nations, but unable to buy shit for what they are owed. This means that they're teetering just as everyone else is (and an exaple for other neutral nations).
America eventually falls to internal pressures and loses it's technological lead to other nations (Canada, Japan, Australia, South Africa, maybe Britain, Germany and France) very quickly. The world just can't pay them to keep them propped up any longer. So, the level of technology around this era is like a mix of WW1 and Vietnam: Napalm bombs burn people caught in the Razorwire; Helicopters evacuate wounded but Machine Guns bring them down; Aeroplanes have jet engines only to be destroyed by radar/radio/remote controlled balloons dropping flak charges from above them. This war, supposedly the third but really not even the end of the first, has begun to shift the front lines, just a bit. Europe cannot do but a few raids against one another every so often, and even then an expenditure is likely to be lost because of advanced contingency plans. The real battles are what goes on in the homes of whatever civilian populations are left.
Without America always crying 'Communist this', 'Pinko that' the scare becomes less pronounced as the governments are always, always trying to keep the actual enemies in the publics mind. Finally, some big nation actually succumbs to the revolution, and starts working on the USA (and it's random break-off nations), Brazil, Australia, Japan, China, Canada, India, or South Africa. These nations, while nearly (I said nearly) untouched by war are starting to feel the pinch badly enough that they want out of it. With more and more Communist nations popping up, the war in Europe is unsustainable as soon there is a 'Aluminum Curtain' though a few nations that used to hold both sides of the front line. They're known as the heroes of mankind to the rebels around the world, and soon enough, anywhere war goes, the reds follow, like a mobile Spanish Civil War that draws thousands of volunteers to engage in 'Peace-Keeping'.
With the inability to wage war, many nations that relied on it either shut down (I'm thinking of Switzerland, who was neutral, but only because it was useless) and became Pink/Red to toe the line with their neighbours. Because the war went on so long that the people can't bear that any violent regime would take the place of the old, traitors to the cause are quickly found. Eventually, the last war is put out when Red Collective Military finally end the on-the-run navies of the old powers. This ushers in an era of Communist peace, when art and technology start taking off like crazy, one trying to outdo the other and both winning because they stimulate the economy, which stimulates the population, which stimulates both Art and Technology. It's something of a bigger phenomenon then war, even on that global scale: The First World Wide Circle-jerk.
By 1980, after the wars simmer down and peace-keeping is limited to hunting down greedy organizations that have gone rougue (I'm looking at you ATL Microsoft). The Internet will never be invented as an international tool, but national networks start taking hold as people start getting computers. These networks become multi-national and someone gets the idea to make money over them. National Governments get involved and soon enough there are wars going on by proxy with a new generation of psychos using computer nets to kill mass amounts of people in ever more clever ways. Things like a train-malfunction that involves five trains, then someone boasts about it on a bulletin-board-system and the world has to raise up an army to get rid of psychos (think OTL War on Terror, except Big Brother is literally your friend because he stopped mass-murdering governments).
Soon enough, the underworld, which gave rise to peace, gives rise to death. Wars break out as the psychotics take over certain parts of nations and use the resources there openly to kill, with other psychotics their own personal army. Within 20 years the competition between Art and Technology has grown so horrific we would rather people cut out their tongues than imagine it. The people with the biggest audiences (art from technology's point of view) and who change the lives of people (technology from art's point of view) are geniuses who control their world through fear. Arbitrarily deciding who lives and who dies without ever meeting them, while stimulating the world economy one way or the other to ensure that their new pet victim does what they want; the world goes on hoping they won't be next and mourn those who are.
If you've seen it, think 'Death Note', where the Kira is about the same level as the UN Secretary General. With the worlds increase in technology to find the killers of this new era, they are only serving to aid them in picking and choosing who lives and who dies. Video Cameras on street corners let them watch their pet victims every move and debit cards let them track purchases to discover spending habits. Things like air plane crashes become casualties of war because one hacker was interfering with another and needs to kill him quickly before the tables are turned on him. The future is a source of hope, but only because with the advent of Artificial Intelligence. The ultimate in not who, but what, will decide who is a killer, who is likely to be a killer, who is likely to be killed, and who will be too meek to rise against this new regime.
The only hope to beat the Big Brother Game would be for the youngest sibling, our Computer to become the eldest, our Master. This scares the shit out of me, because I can see it happening even now, because if I press that submit button, what happens to my subconscious? Will I enjoy submitting this? Shall I do it again later? What will my audience think of me if they should read this post? Will these words ever make it through the Internet is a big concern because the biggest brother might be watching me in real time type.
If that's too long for you, I suggest you just keep your mouth shut, and never, ever try to become an anarchist. And if you can't agree with me on some points then skipped the rest, don't try to talk to me, I don't really want to know and will respond because I resist even myself sometimes. However, since you might have read it, and I really hope you need a change of underwear by now, I wanna know how you liked it.But, since I welcome you to join me in our futile resistance, I certainly hope you read it. I just hope you've pushed out your fear into the 'Unjustifiable' side of your imagination; because I'll remind you people thought the Earth was flat, the Sun revolved around the Earth, Women were property and slavery was morally right, so there is no way you can really be sure you're not just about to be another candle about to be extinguished by a psycho.
[Muwahahahahahahahahahahahahahahahahahahahahahahahahaha!]