Hello! You may have seen some of my responses on the other thread. I objected to calling this intervention an "invasion" because I believe that misinterprets American motives for sending men to Russia, as well as their actions there. I'm glad you asked the question here, because it will allow me to give a more scholarly response.

Let's start with the numbers. In total about 11,000 American troops went to Russia between 1917 and 1919. 5,000 men, "the Polar Bear expedition" went to Murmansk and Archangel in northern Russia, where they joined a larger, British-led taskforce. The rest were in Russia's Pacific port of Vladivostok. During the course of this intervention 222 American soldiers died.

What were American troops doing in Russia in 1918? This was a question being posed by Americans themselves at the time, including the troops in Russia. The answer is complicated, because even at the time there was no agreement what Americans were supposed to be accomplishing in Russia, nor even that they should be there. Unfortunately, the issue was long and complicated at the time, so please bear with me as I try to answer it.

The Lead-Up to Intervention

The Russian Provisional Government collapsed in October 1917, replaced by the Bolsheviks. This worried the Allied Powers of World War One, because the Bolsheviks promised to make immediate peace with Germany. That would entail a strategic disaster for the Allies. If the Eastern Front folded, Germany and Austria-Hungary would be able to ship millions of men to the Western Front. They could also negate the effects of the British blockade of Germany by seizing Russian agricultural land. On top of it all, the Allies had sent massive amounts of valuable war material to Russia during the war. Because of Russia's miserable logistics and war-planning, most of this material was still sitting in ports in Archangel and Vladivostok. The Allies worried that now the Germans would literally turn their own weapons and material against them.

Therefore British and French war-planners proposed to send troops to the Eastern Front. Hopefully they would be able to secure war supplies from the Germans and force a continued Central Powers commitment in the east. The Allied forces could there act as the nucleus of a revitalized Russian force that would keep on struggling against the Germans. The Allies were not particularly picky about whether the Russians they supported were Bolshevik or anti-Bolshevik. As long as they continued to fight the Central Powers, the Allies would help them.

Many Allied planners actually pegged their hopes on the Bolsheviks in early 1918. Lenin's forces were still fighting the Germans, and the Bolshevik government looked like it might be stronger than either the hopeless Tsarist administration or the unpopular Provisional Government. Unfortunately for the Entente, Lenin was an impossible ally. He published secret Allied correspondence with the Tsarist government, repudiated Russia's enormous debts to Britain, France, and America, and finally made peace with the Central Powers at the Treaty of Brest-Litovsk in March 1918.

The Allied military liaisons in Russian therefore turned to the Bolshevik's opponents as potential allies. Many of these attachés, like the British General Sir Alfred Knox, were also conservatives with personal distaste for socialism. These officers, a lot of them relatively junior ranks, championed the anti-Bolshevik cause as focus of Allied efforts in Russia. Nevertheless, the Allied governments did not really care who they helped. The first Allied troops to land in Russia was a force of Royal Marines that landed in Murmansk on March 6, 1918 - with Lenin's approval.

In Russia we sometimes call it an invasion because propaganda outlets say so (but not respected historians, of course). There was a concentration camp on Mudyug island in the North of Russia and there are still monuments dedicated to the victims of the intervention, but no one calls it an invasion excepting those who's aim is to promote hate and mistrust towards the West.

The goals of the US were to secure supplies of munitions and armaments in Russian ports and help the Czechoslovak Legion leave Russia. The only person who wanted "to strangle at birth the Bolshevik State" was Churchill, but his views were unpopular both in Britain and the US.