Final answer:
President Wilson dispatched troops to Russia in 1918 to subvert the Bolshevik government, support the White Russians during the civil war, and demonstrate U.S. opposition to socialism, which later led to strained U.S.-Soviet relations.
Step-by-step explanation:
President Wilson sent thousands of troops to Russia in 1918 primarily to subvert the new Russian Bolshevik government. After the Bolsheviks, led by Vladimir Lenin, seized power in November 1917 and exited World War I through the Brest-Litovsk Treaty, a civil war ensued in Russia. The U.S., along with other Allied forces, supported the White Russians (counterrevolutionaries) against the Bolsheviks. This intervention was partly due to the Allies' fear of the spread of socialism and to support forces opposed to the Bolshevik regime. Although this intervention was not large enough to be militarily significant, it demonstrated the United States' hostility towards Socialism, which in turn laid the groundwork for future strained relations between the two nations.
Wilson's decision to intervene was also influenced by his foreign policy and the political climate in the United States at the time. The American intervention in the Russian Civil War was controversial and reflected the complicated relationship between the pursuit of democratic ideals and the realities of geopolitical strategy during the turbulent period following the First World War.