I'm leaning towards self-interest as it started during ww1 when the allies wanted to resurrect an eastern front and prevent the central powers getting materials sent by the allies to russia. On the other hand the allies had clear distain against Bolshevism and continued their war even though WW1 had ended. Then theres also the split answer where they didnt want Russia to be communist / socialist cause that might mean losing a trade partner and former "anti-german" ally. Anyone have an idea?
ps. With Allies I'm particularly interested in the US,UK and France
Hey there!
So I wrote an answer to a similar question a few days back, which is here.
To recap and summarize that a little bit:
Initial discussions about Entente/Allied intervention in Russia began in March 1918, in the Supreme Allied War Council under Field Marshal Foch. Wilson went back and forth on supporting this, and didn't agree until May, when fighting broke out between the Czechoslovak Legion and the Bolshevik government.
In the meantime, the Bolsheviks had signed the Brest Litovsk Treaty with the Central Powers, ceding large chunks of territory and in effect allowing some million or so Central Powers soldiers to occupy various parts of the former Russian Empire.
The initial concern was indeed to protect war materiel that had been shipped by the Entente/Allies to Russian ports, notably Murmansk, Archangelsk and Vladivostok. US forces in particular were supposed to guard these materials to prevent them falling into Central Powers hands (the Germans were intervening in the Finnish Civil War at that point), to provide general peacekeeping duties, and to "promote self determination", which was incredibly vague. The Japanese had forces also in Vladivostok, and while there was much debate in the Japanese cabinet over precisely what those forces were to do, the general thrust was to protect Japanese interests in China and build up local forces that were reliant and favorable to Japanese rule. These forces landed in August 1918.
The German High Command had plans drawn up in "Operation Capstone" to occupy Petrograd as part of an offensive towards the allied forces in Murmansk and Archangelsk, but the German Foreign Office preferred strengthening economic ties with the Bolsheviks instead, and the armistice was signed before any further German military action was taken.
After this point, Entente/Allied forces were more openly pro-White and anti-Bolshevik, especially in the Murmansk/Archangelsk area under Admiral Edmund Ironside campaigned in connection with Evgeny Miller's White army (these forces eventually withdrew in August 1919). A French and Greek force landed in Ukrainian ports in November 1918 ostensibly to oversee German withdrawal according to the armistice terms, but also ended up fighting Bolshevik forces before leaving in March 1919. A British naval support was in the Baltic supporting Estonian and Latvian independence movements from November 1918 until 1920. The forces in Siberia remained until June 1920, except for the Japanese who remained until October 1922.
The Caucasus also saw a wide amount of intervention, with Germany occupying Georgia and the Ottoman "Army of Islam" marching on and finally taking Baku in 1918, countered by the British "Dunsterforce". At the Ottoman armistice, Central Powers forces left the Caucasus, and were largely replaced by British occupation forces, who in turn finally left in 1920 (the southern Caucasian republics spent much of that time fighting each other, fighting the Red Army, and fighting the Whites).
The goals of these interventionists were very vague and contradictory, especially after the armistice, and often participating nations' foreign ministries and military establishments were in disagreement. In theory the First World War was just under armistice until June 28, 1919, when the Versailles peace treaty was signed, so operations in Russia were effectively contingency operations in that conflict - once it was over, there was very little public or military appetite for continued participation. As it went, the intervention forces were too small to make much of a difference (the big exception here being the British intervention in the Baltic, which was instrumental in helping Estonia and Latvia win and secure their independence), but big enough for the Bolsheviks and later Soviet historians to claim that their victory in the civil war was against a wide array of domestic and foreign enemies.
As far as whether the Allies were intervening to defeat the Bolsheviks and secure trading partners, I would say the answer is no. The major economic sticking point that the Entente/Allied powers had with the Bolsheviks was the latter's repudiation if tsarist era debts, although this was not necessarily a sticking point that forced matters towards war (the Bolsheviks and Germans had actually negotiated an indemnity payment and renewed economic relations in August 1918). The Allies were actually blockading the Bolsheviks in this period, in no small part because they feared supplies falling into German hands. In the event, the British negotiated a trade agreement with the Bolsheviks over 1920 (it was ratified the following year). France (which had invested more heavily in tsarist Russia), was much more anti-Bolshevik, and also very concerned over guaranteeing tsarist debt, so they took something of a harder line, but nevertheless resumption of trade with Russia was seen as coming through making peace with the Bolsheviks, rather than continuing to support movements fighting against them.
Hope that helps!