At Sea
POD 1. 1917: Zimmerman keeps his yap shut, the popular belief is that the telegram is an English forgery. A British minister is given a berating as it backfires on them. American war enthusiasm is dimmed slightly but still overwhelming pre-Entente as weekly headlines of American children, women, and men lost at sea against unrestricted submarine warfare. Merchant men are being armed as per IOTL against the unchanged unrestricted submarine warfare while diplomatic relations are severed. Admiral Henning von Holtzendorff seems to be vindicated on his prediction of American neutrality, for now. Having lost a high of 800,000 shipping tons in April the British start organizing and implementing a convoy system and the tonnage lost steadily declines down towards 500,000 tons a month; contrary to Von Holzendorff's predictions the British refuse to give up. While current losses exceed Entente shipping production, the British, Dominions, and French started the war with over half the world's shipping at 23 million tons. At a exchange rate of 55,000 merchant tons and 105 sailors (can be drawn from worldwide pool) per submarine (quite the technical construct) and 35 submariners (must be trained at least 9 months with technical skills) attrition isn't on the side of the German Empire as British production and ship purchases from America keeps losses manageable.
There is a brief scare in France as imports seemed insufficient to prevent hunger and the French Minister of Commerce Etienne Clémentel in control of French maritime transport, goes to London in Autumn 1917 to seek relief; this will lead to the Allied Maritime Transport Council like IOTL that not only pool shipping resources but also helped implement efficiencies against port congestion and ship waiting times as per IOTL.
POD 2. As American causalities mount two votes are proposed by Wilson to join the war, but like Versailles IOTL Wilson's desire to play the hero while neglecting congresses concerns backfires as congress disagrees with Wilson's over-eagerness wanting to go over some details and inadvertently end up in a mud-slinging match both times. Regardless the majority of Americans are pro-Entente while hate for the Germans killing Americans rises. The British and French, fighting the Germans killing innocent Americans gain better credit terms; while they may not be at war the American resentment is seething.
On land
The provisional government, as per IOTL believed that their military is revitalized just because they replaced the head and plans continue for a July offensive ignoring all the seething troubles of the Tsarist government. This plan was voted on before OTL's American DOW and nothing material changes in Russia, the hope is still to use an offensive to gain prestige, then deal with all the internal troubles. Kerensky as per IOTL is giving speeches infront of hand-picked crowds that are enthusiastic to end the war, but by going home instead of fighting Germany. Blind to the sheer war-wariness and more concerned about legality and precedence of popular demands of land reform, serfdom, and food the provisional government decides to hold an assembly in September. Meanwhile the peasants and soldiers of Russia, who gave two shits about legal precedence or constitutional legitimacy votes with their feet by walking home and seizing noble lands; the majority of times the land records are burned and the manor's occupants told firmly to get out or else. Meanwhile the cities grow more restless as the new government seems just as bad as the Tsarist gov it replaced in getting food. Many setup their own councils (Soviets) often with the SRs, often in alliance with the Bolsheviks as IOTL. America's absence has minimal effect as the strait of the Bosporus remains closed and shipping is lacking regardless.
On the western front Nivelle continues his preparations for an offensive (once again pre-dating America's DOW) decided in the Chantilly Conferences in 1916. Despite reservations from Petain the overwhelming majority of French civilians, leadership, and soldiers want to reclaim French land and their discontent was with the inefficiency of the previous offensives as opposed to the idea of offensives. Just like IOTL, neither the French nor British planned for an American DOW, it was nice but they had no idea if or when it might happen. The British give their support and join the offensive contingent on French-assistance; Nivelle will mess this up.
Both offensives fail. The French sack Nivelle promoting him to African theater command, yet the old guy just sticks around headquarters for weeks as no one wanted to deal with the awkward conversation just like IOTL. While there is a brief antiwar revolt, French soldiers can simply write to their representative and many of them do incontrast to the military dictatorship in Germany. Petain takes over, gives the men better conditions, more rest, and sets the army on a defensive posture for at least the rest of the year.
Lacking manpower, the French start implementing mass-colonial conscription; while opposed by colonial big whites and definitely complicates metropole-colonial relations post-war it was seen as the lesser of two evils. Many colonials will sign up, after all the French had already made various promises of autonomy, privileges, and such when peace was achieved at the start of the war; some of course sign up for the pay which even at a fraction of a Frenchman's is quite the sum back home.
It looks like its up to the British for 1918 who still has plenty of men to draft. Meanwhile various dominions begin or widen conscription, while contentious most Dominions are British or first generation British and support is overwhelming except in Quebec. Horrified by the seemingly pointless causalities taken for a few miles British PM Lloyd George considers with-holding men from conservative favorite Hauge, begins to (and by implication sabotages the British war effort for political gain) but quickly reverses course when the Germans seem to be on the ascendant after fall in the East.
In the East, many soldiers simply refuse to attack, those that do are the most reliable and elite of the remaining Tsarist-now Provisional forces. The attack is directed at the weaker Austrian forces, unknown to the Russians the Austrian army had mostly integrated into the German army and the quality was uniform across the Eastern front. The attack is allowed to run out of steam before the German army counter attacks dealing a devastating blow to Russian morale and Kerensky who betted all of his legitimacy on winning a good peace.
Despite the failure, Kerensky's delusions deepen as he alienates the Cossacks (the last militarily powerful pro-provisional force) as per IOTL. Bolshevik elements call for a coup to dispense with the dual governing arrangement between the Provisional Government and the Soviets, nothing happens IOTL as the majority of Russians are tired and hungry not caring to fight for either side; yet Kerensky in his delusion interprets this as a lack of support for the Soviets and by default a massive amount of support for him. Over the course of June, July, September Kerensky tries to call an assembly for legitimacy, only the Provisional Government assembly doesn't shut up and obey and goes off to make his own assembly just as IOTL, with hookers and blackjack in the Tsar's palace (not yet confirmed).
In a vacuum of power after the breakdown of central authority, the Bolsheviks seize power and proclaims land, peace, self-determination, and food. Given that Bolshevik power is limited to parts of Moscow and Petrograd and a tactical alliance with the SRs that run the majority of Soviets there was little else they could've done. Most remaining soldiers take this as permission to go home, looting along the way to sustain themselves while peasants ratchet up the land appropriation. In contrast to their proclamations, the Bolsheviks immediately setup the Cheka; a secret police accountable to no one, start confiscating food from the countryside to sustain their urban powerbase, shutting down all political opposition, and accepting minority independence on paper; ie arguing that while the Ukrainians should be free, the Rada isn't representative and we should have an non-rigged election later.
Across the empire, with the breakdown of central authority many old grudges are coming to the surface across class, religious, and ethnic lines. In Finland the militant aristocratic right strikes first; hoping to crush the socialists and gain independence, meanwhile the majority reds and socialists are caught flat-footed as they also wanted independence, but peacefully. There are many more instances but that's a story for another time.
To conserve troops and to fight in the east, the Germans pull back to the Hindenburg line in March. The deplorable state of occupied France they leave behind shocks the world and further enrages the French. At the end of it, the Germans tire of Bolshevik stalling at Brest-Litovsk and decided to attack hard against... nothing. Nothing expect the token defensive positions and come within a hundred miles of Leningrad (as IOTL) and the minority of Bolsheviks led by Lenin sues for peace under harsh terms; trusting that soon revolution will come to Germany and the other imperialist powers and they can reverse the losses. Regardless of peace or war, the long-suppressed tensions of the Russian Empire are finally unleashed and there is no turning back regardless of what figurehead is in charge.
To many peasants the Bolsheviks were worse than the Tsar, stealing food, beating the reluctant, all with a excess spurred by revolutionary zeal and the gluttony of hungry men. Adding to that the Germans try to extract what food there's left that they can get their hands on in Poland and Ukraine; the resulting 100,000 tons (just as IOTL) is a drop in the bucket for Germany, let alone Austria or Bulgarian.
Germany:
Trading a million men in occupation fraternizing with socialists for 100.000 tons of grain is a bad deal by all accounts, but the prideful Hindenburg refuses to admit as such and opts to continue the trend from 1915 of scape-gloating minorities, pitting regions against each other, soldiers against officers who receive better rations, POWs, women, children, and anyone who isn't working for the war-industries or military is deemed as "stealing" food from the deserving just as IOTL. (sounds like Nazi-lite doesn't it?). 3 years of prioritizing nitrogen for the military instead of fertilizer, of farm boy drafts, of farm animal drafts/slaughter for the imminent victory every season since 1914, and of the price controls fast finally hitting the breaking point. Faced with confiscated/slaughtered animals, drafted sons, less fertilizer, and price controls making profits impossible many farmers decide to grow for only personal consumption.
By 1917 most Germans, while supportive of market controls found the government to be “in control of nothing” and even to have sanctioned profiteering, suggesting that people who did not follow the rules should be put into prison, while those who did follow the law belonged “in the nuthouse." as per IOTL. On average, a healthy German would've lost 40 pounds by 1917 (just as IOTL) and the specter of disease and famine began to rear their heads. The average German surveyed listed sourcing food as both the number one concern and the greatest time spent per day; valuable work hours are spent queuing in line, searching unofficial markets, or just plain sick instead of industrial activity. Only a hundred thousand or so die this winter, but the food situation can only worsen and OHL decides that since USW has failed to break British morale that it must finish the war soon.
AH: By 1917, one of the chief architects of the war Conrad von Hötzendorf had already destroyed the Imperial Army several times and had implemented indiscriminate drafting since 1915 ripping away machinists and farmers need for the war. In march 1917, after so much wasted lives Conrad von Hötzendorf is finally dismissed and given the title of count; he will spend the rest of his life denying all wrongdoing and blaming everyone else (particularly the imperial court and Germans, the only ones capable of exonerating him). (just as IOTL, he'll brood in hell for a quick moment before being clawed apart by millions of imperial subjects and Serbians.)
At 5.638 million tons imperial food production is only 60% of the pre-war 9.43 million tons just as IOTL, last I checked the Austrians weren't importing from America. First, the decline is partially due to the repeated occupation and scorched earth of Galicia and Bukovina which accounted for over 1/3 of imperial production. Second the repeated destruction of the imperial army has led to a massive labor shortage, lack of fertilizers, lack of draft animals, lack of grazing herds. Unlike Germany, AH had only lacked Phosphorous and Nitrogen fertilizers but had potash in abundance; which has lead to 3 years of overuse and soil depletion; something post-war farmers will complain bitterly about. Also unlike Germany AH price controls discouraged grain in favor of animal feed in addition to discouraging general production. And unlike Germany AH was hit by climatic disruptions, which further lowered food production. (all as IOTL)
In contrast to the more generalized German market the internal AH market was relatively specialized, leading to worsening distribution and oddities such as Austria being self-sufficient in dairy, but severely lacking in meat and grain. As transport broke down the Empire's agricultural specialization has left the Austrian core starving; while it made sense pre-war to produce only perishables around Vienna and import durable grain from Hungary this was no longer the case.
In the midst of all this turmoil, old agitations for democracy, equality, national self-determination, class-wars, and were reaching a boil. Riots and strikes had already broken out in the cold and hungry winters of 1916. More frightening still was the adoption of the Russian slogan "All power to the Soviets!" by the moderate democrats, not that Vienna bothered to make the distinction. In reaction to all this, the military high command that had stumbled into this war decided to inspire "military discipline" to stop the unrest to little effect, blame the various ethnicities they commanded for the failures of command, and come September blame the returning prisoners of war from Russia as cowards and traitors sending them to military re-education camps (just as IOTL, I can't make this stupidity up, how arrogant do you have to be to actively spite your own soldiers?). Despite all of this, order still prevailed and the army obeyed while their stomachs rumbled louder every day. Meanwhile non-German and Hungarian POWs in Entente camps flocked towards the foreign legions with the promise of freeing their homelands.
Bulgaria; starting from a feudal-rural economy the tiny nation of 4 million has mobilized an amazing quarter of its population. This is especially impressive given that it had lost its most fertile land in 1912 during the second Balkan War and had not recovered its herds or material stocks. Yet unable to feed itself, arm itself with heavy weaponry, or push into the mountains of the Macedonian front the cries for help grow ever louder towards Berlin and the heavens.
Ottoman Empire: despite the majority of the country opposing the war, being unready for war, and having just suffered the loss of the economic heartland in 1912, and undergoing sectarian strike, Enver Pasha said "fuck it I'm gonna burn it all down in a war and a new and improved Ottoman Empire will rise from the ashes" and is now getting to reap his fruits; except instead of a renewed Ottoman Empire its looking more and more like a renewed Turkish nation as regions breakaway.
In no small part thanks to Pasha's amazing incompetence entire armies had died to the elements before even meeting a single Russian and the same starvation, destitution, and chaos is present like the other central powers. (same as IOTL, bit colorful)
