The economic sanctions that the US has imposed on Russia primarily serve to take Russia out of the energy and arms markets. The US has its own economic and energy positions in Europe and this is a way how to maintain it. This means that they use political reasons to promote their own business interests.
In August 2017, the US imposed the latest sanctions on Russia over its alleged interference in the 2016 U.S. presidential election, its annexation of Ukraine’s Crimea region and its involvement in Syria’s civil war. New sanctions are introduced on entities doing business with Russian military or intelligence agencies, companies involved in Russian off-shore oil projects, and those participating in Russian oil or gas pipeline construction within Russia.The US Congress also committed to only apply sanctions after the country's allies, including the EU, are consulted.The economic sanctions imposed on Russia serve as an expression of disagreement with the Russian annexation of the Crimean Peninsula in 2014. However, it is not the US instrument used to make them better traded in the energy and arms industries. Sanctions were imposed not only by the United States, but also by Canada, Japan, Australia, New Zealand, the European Union and other 7 European countries outside the EU, including Ukraine itself.