Timeline!
POD: 1925- Lenin's Last Will And Testament is published in special edition of Pravda, at the instigation of the leftist wing of the Party (although many blame Trotsky personally).
1926- Stalin is criticised in the Fifthteenth Party Conference by Trotsky and Thomsky for the purging of Zinoviev and lesser anti-NEP party members. The mere fact that these denunciations are made at the conference is an indication of the uncertainty and unsupportiveness of his rightist allies (e.g. Bukharin) over the criticisms in the testament, or at least the fact that they were common knowledge.
1927- Stalin removed from post of General Secretary, given post of Commisar of Heavy Industries. Later in the year, a Politburo comprimise sees priority given to Industrialisation under the Rapid Industrial Capital project (known as the "First Movement", by 1929, industrial production will have risen between 25 and 75%.
1929- Stalin rejoins the front rank of the Politburo (although he never left the politburo itself. Kamenev calls for the dissolution of the NEP, but loses a vote. It remains official party policy.
1931- Mass purging of Party Membership (approx. 30% reduction). Many of the older party members feel it unfairly favoured the younger, less intellectual part of the membership. By the end of the year, Stalin and Bukharin call for a "Second Step/Movement" of industrialisation. This will lead to effectively doubled production by 1936, and requires the export of Soviet grain, largely to Europe and the Middle East.
1932- Bukharin calls for caution as grain prices soar and there are reports of widespread reports of terrible industrial accidents and the breaking of tools. He is overruled by Stalin and by the pro-interference Leftists (except, significantly, for Trotsky).
1933- Famine in the Ukraine and Causcaus. Approx. 4.5 million will die by 1934. Note that this is significantly less than OTL. Bukharin narrowly avoids dismissal for criticising policy, and Zinoviev is appointed Minister for Agriculture. Kirov, on a tour of new rail lines in Vladivostok, takes credit for a Soviet victory in a skirmish with the Japanese.
1934- Kirov made Commander of the Red Army.
1935- Tensions build with Finland and Poland. Kirov calls for preemptitive strike on Polish defences under construction, is overruled by Politburo. Molotov returns on New Years day bearing a Non-Aggression treaty with Hungary and Poland, known either as the Warsaw Pact or the Solstice Pact.
1936- Britain opens trading with USSR after Solstice Pact relieves fears of British pressure on the Polish to fight. Kirov starts reforms of army, in part to integrate mechanised forces constructed since 1927 into main tactics. Is interrupted by outbreak of war with Finland after allegations that a Finnish trawler was torpedoed. Molotov secures German and Swedish neutrality, while the Danes and Norwegians give aid to Finland short of military involvement.
1937- Spring War. Russia makes limited advance with quite heavy losses, then waits out the spring melt. An advance is planned for summer, before Kirov changes tactics at the last moment, and allows a Finnish counter-attack to over-extend, and crushes the Finnish main army in a pocket, under intermittent bombardment by heavy artillery and the Red Air Force. This allows a peace to be signed with no loss of face by the Russians. Trotsky calls for support to German communist party, and for an escalation of involvement in Spain. Only the latter is granted, and several squadrons find themselves sent from Finland to Spain without a chance to get new uniforms, nicknaming themselves "White Crane Squadron" for their migrantory habits. Trotsky travels to Paris for meeting of world Maxists, and lies to world about Russian involvement in Spain- although he is correct to deny any Soviet ground forces. Spain eventually becomes a constitutional but fiercely conservative monarchy under King Carlos I (VII) of the Carlic dynasty.
1938- Kamenev and Stalin call for compulsory collectivisation. Instead the NEP is abolished officially, and the "Third Step/Movement" calls for agricultural reform, and simultaneously, Kirov undertakes the "Iron Step" or "Forth Movement" of military reform. Trotsky calls for commissars to be included in reformed Red Army command as equal to officers, but is deemed "inefficient and liable to cause disciplinarian problems" by Kirov. Red Army Commisars instead form a parallel chain of command.
1939- Hitler invades Poland and then France. Poland pleads with Russia to intervene, but instead Molotov, in a fevered 48 hours in Berlin, secretly agrees to a truce whereby Russia may take the Eastern 1/3 of Poland. Despite the lack of serious fighting between Red and Black forces, Polish citizens look on Russia as their defender. Russia signs defensive treaties with much of the Balkans. Hitler invades France almost immediately upon the truce, but the advance, delayed as it is a fortnight from OTL, is not quite as rapid- more Allied troops escape from Channel ports, and Dunkirk does NOT happen. Famous footage is taken of the demolition of the Belgian royal summer palace rather than surrender the throne to German hands. Signing of defense agreement between Norway, Sweden and Denmark.
1940- Invasion of Norway and Denmark. The USSR sends some supplies to Norway, but mostly remains neutral. The British Naval Air Arm torpedo two German destroyers in Oslo harbour. Quisling murdered, possibly by British agent. Nevertheless, the Germans take southern Norway and all of Denmark. Sweden signs treaty with Russia- if Finland assists Germany in any invasion, the USSR will attack Finland- but not Germany. Surprisingly, this is accepted by Ribbentrop. Finland attempts to avoid its commitments to invade Sweden with Germany, but is convinced that the war will be too swift for the Soviet Union to actively fight.
1941- Invasion of Sweden. Sweden supplied with food and ammunition via Artic railway seized during Soviet invasion of Finland. North Norwegian forces formally surrender, with large numbers crossing into Sweden, but resistance continued by civilians and ununiformed forces. Fall of Singapore, and the Russians launch a raid into Manchuria in conjunction with Communist Chinese forces.
1942- War declared between Soviet Union and Hungary, Germany and Japan. Kirov is outmanuevred in Politburo (with hints of "Thermadore) and sent to oversee Japanese campaign, much to his disgust. Trotsky given command of "European Front" (Poland and Hungary) and the "Artic Front" is given to regional army commanders, most notably Zhukov. Helsinki taken. Finland surrenders. By 1943, Sweden is essentially a Soviet puppet state. America declares war on Japan and Germany. No Pearl Harbour, but a naval battle provides similar provocation to enter the war, at less cost to America. In the 1970s, it wil be revealed that the Americans attacked first, but that's beyond the scope of this section of TL. US forces invade the Phillipines and North Africa.
1943- The "Volga Order" is given, whereby Soviet Forces are refused permission to retreat across the river and industrial plant is shipped east. It does not really come into effect, but is a cause of friction within the politburo. Operation Balmung, a German offensive, pushes the Soviet forces out of south Sweden, and secures German iron ore supplies, and evolves into Operation Tyr as the Germans push into Finland. Zhukov is recalled to Moscow after questioning an order to purge the Swedish and Norwegian forces allied to his armies of "monarchistic and nationalist-fascist elements" on the grounds of the damage this would do to his relations with partisans. His eloquent and intellectual defence is surprising fo those who do not know he has been coached by Trotsky in an effort to undermine the "Socialism in one county" branch of the Politburo. He is relieved of command and sent east. Kirov is recalled and put in charge of the Finnish Front. There is no evidence of a meeting of the two commanders mid-route between Siberia and Finland, but they began a correspondence. Allied forces invade Sicily, Greece and North Italy.
1944- Soviet forces begin advancing back into Poland. American troops are on last leg of island hopping campaign, and both US and Soviet air forces bomb Japanese cities heavily, while the Soviets drive Japanese forces in China into a pocket in Manchuria. A Japanese order is given to commit mass suicide, but it is lost in transit, and only half the army voluntarily commits suicide. The battle of Helsinki turns the tide in Finland, with two Panzer armies and a battalion of Tigers dissapearing. Zhukov becomes a national hero after he personally destorys a Tiger with a captured Panzerfaust. Bukharin suffers heart attack, and is temporarily relieved of duties in favour of Comrade Stalin. An uprising by Polish forces in Warsaw is supported by air drops by both Soviet and US planes, but is allowed to almost be crushed before a Red army tank column reaches the city. First mass use of AVS automatic carbines by Soviet troops. Soviet forces join up with Yugoslavian partisan army.
1945- Meeting of American, British and Soviet troops in China. With the realisation that the Emperor will not surrender, the bomb is dropped. The Politburo reprioritises the seizing of Norwegian heavy-water plants, and the German physics laboratories in Berlin. Soviet troops reach the German border and link up with American forces in Greece. Mussolini captured, escapes through the sewers of Rome, and travels through Algeria to Spain. Otto Skorzeny leads a break-out from Stockholm, contrary to the Fuhrer's orders to fight to the last, and declares himself Generalissimo of Sweden, promising democracy (post war) and freedom from the Bolsheviks if the Swedish will support him. Military coup against Hitler ends with seige of bunker. Mass execution of German-based SS, and many executions at the front. Ribbentrop negotiates truce with Allies, and Axis forces begin withdrawal from Balkans and Scandanavia. Fuhrer's bunker forced open to discover poison gas had been released, killing approximately 300 people inside.
1946- Otto Skorzeny declares intention of running for German president in tour of America, but is shot at by a Ukranian immigrant in Chicago, and loses his left arm. Military occupation of Germany by Allied forces, Sweden and Norway rebuild but Finland becomes a Russian satellite. Partitioning of Poland.
Trials of Nazis who didn't die in the bunker and concentration camp guards, but general contentment to claim the evil died of Zyklon-B in Berlin. Denmark requests departure of Allied forces, and forms-semi-fascist government.
1947- Czechoslovakia and Yugoslavia vote to become socialist. Italy erupts into civil war, with support from Spain and the USSR. America threatens to intervene to little effect. Swedish royal family decline place in new constitution in favour of republic.
1948- Skorzeny wins power in Germany on democratic but anti-Bolshevik lines, with support from the Catholic Church crucial. Poland split into the "two Republics", with Warsaw partitioned. Norwegian king re-coronated in still wrecked Oslo cathedral.
1949- Chinese communists officially in power. Denmark bows to pressure and allows free elections. Austria breaks with Germany. German communist party leaders arrested for treason after allegedly planning a coup. USSR protests, and demands Western occupation of Poland ends. Mass exodus of Polish democrats to Germany, Austria, Hungary and Sweden.
Still needs work on Japan, and I'm not sure the Allies should invade Europe...