This is a topic that likely most students of history remember, but most Americans never learned - The Russian Civil War of 1918-1920 and the Allied intervention on behalf of the White Army forces. Even fewer Americans are likely to remember that we committed almost 13,000 troops to the invasion forces and that 275 Americans lost their lives on Russia soil.
The Regiments website is a military historians dream page, with extensive detailed descriptions and dates of various wars in which the British Empire was engaged. There is information on uniforms, regiments, and formations as well.
But for our purposes today, we are interested in the Russian Civil war. The Allied Forces at the end of World War I. As Regiments discusses the causes of the civil war (which might be debatable from the Russian point of view):
Russian military reverses, heavy casualties, and economic hardship contributed to the Russian revolution which withdrew the country from the First World War, releasing German forces for an offensive against the other Allies on the Western Front. Chaos led long repressed nationalist aspirations around the perimeter of the Russian empire to declare independence. Bolshevik excesses soon began to coalesce various factions, and civil war broke out. Japan was the first to exploit Russian weakness with an apparent view to annexing the maritime provinces in the East.To paraphrase Vizzini: They fell victim to one of the classic blunders. The most famous ... never get involved in a land war in Asia ...
The British, French, and Americans hesitantly and fitfully intervened with a four-fold goal:
1) prevent Japan from creating an empire in the East,
2) prevent massive Allied stores originally sent to the tsarist armies from falling into German and subsequently Bolshevik hands,
3) assist the White Armies in overthrowing the Bolshevik regime and bring Russia back into the war against Germany,
4) rescue the Czechoslovak Legion trapped in central Asia so that they could rejoin the war against Germany.
Allied intervention joined White armies on four fronts:
1) White Sea ports in the north,
2) Black Sea ports in the south,
3) Caspian and Caucasus region, and
4) the Far East.
The plans of some Allied politicians called for advancing with the Whites on all these fronts to link up in the centre and crush the Bolshevik regime.
But I digress. Regiments provides a detailed chronology of the Allied forces invasion and eventual withdrawal from Russia two years later. 160 Americans were killed in action and another 168 died by other means (disease, cold, famine, STDs). All wars are chaotic - the Russian Civil War perhaps more chaotic than most, as Regiments explains:
Although the civil war fronts fluctuated wildly, the Bolsheviks gradually developed discipline, and had the advantage of defending the central Russian homeland. Opposition White forces never developed military or political cohesion, and were hampered by appearing to be the tools of foreign imperialist interests. The civil war did much to harden the Bolsheviks from a relatively democratic party into a ruthless and draconian regime, which eventually reunified much of the splintered Russian empire by force.
Allied intervention was insufficient to provide meaningful support to the Whites, and the November 1918 armistice on the Western Front removed much of the raison d'etre for intervention, namely to bring Russia back into the war against Germany and protect stores from falling into German hands. Motivated in part by fear of world communism, Allied occupation of Russian territory did much to sow the seeds of distrust which grew into a fifty-year Cold War between the Soviets and the West.