A the Bolsheviks threatened to cut off trade with the United States
The nineteenth European imperialism was motivated by various reasons. The most important of them had to do with the development and growth of a new stage of capitalist economy.
During the 19th century several European countries were changing due to industrial acceleration, which historians call the Second Industrial Revolution. It happened mostly in industry, transportations and communications.
For example, the invention of the dynamo in 1870 soon lead to electric ilumination of cities; the invention of the internal combustion engine allowed for the use of oil and its derivatives as power sources.
This lead to a revolution in transports, virtually reducing distances and accelerating time -- now people would travel and exchange communication much faster than before. The world got smaller and more connected which gave an impression of much more things happening than before.
All of these discoveries and new power sources lead to a greater need of raw material and of consumer markets in order to have groups whom to sell the goods being massively produced. These new necessities would be violently attended through invasion and colonization of several parts of the globe, giving birth to modern imperialism.
Japan was desperate for resources. (Apex)
