Hat tip to Strategy Bridge for a review of a new book on the campaigns in the Russian Civil War 1918-1920, when British, Commonwealth, French, Japanese, Greeks and American troops all fought and died. It is almost a forgotten war, a war that was far from small and was to have profound repercussions on Russia / Soviet Union.

The relevance today? Well this phrase has IIRC been on SWJ Forum before:
While largely a sideshow at the time, intervention in the Russian Civil War holds a variety of parallels and warnings for modern strategists, tacticians, and politicians. Contemporary readers will see analogous situations in Civil War Russia to American involvement in Iraq or Afghanistan.

The book is 'Churchill's Secret War With Lenin: British and Commonwealth Military Intervention in the Russian Civil War, 1918-20' by Damien Wright, published August 2017 by Helion.

The sole reviewer's key passage:
A key component of the British strategy was the flawed assumption that a comparably-sized force of local Russian volunteers could be raised, equipped and trained to competently fight the Bolsheviks, initially alongside the Allied forces and later in support of the White Russian forces, after an eventual Allied withdrawal.

(Then) By mid-1919, it became apparent to British commanders that their locally-recruited Russian troops were unreliable and that the White Russian Forces under Kolchak and Denikin were unlikely to prevail against an increasingly superior Red Army. Whatever window of opportunity had existed was about to close and after more than four years of bloody conflict, there was no public support for continuing a military intervention in someone else's civil war. By October 1919, all Allied troops had left North Russia and by mid-1920 they had been entirely withdrawn from Siberia and elsewhere.