Russia is considering a ban on supplying the US with RD-180 rocket engines. If this ban is put into place, engine delivery to the US will most likely stop all together beginning in 2015.  For the past 10 years, most of NASA’s rockets have used Russian RD-180 engines.
This ban will affect military and nonmilitary space exploration by the US. The military uses the rockets for communication satellites and deep space exploration vehicles. This ban will affect NASA beyond its military launches.
According to the head of the Space Policy Institute, Russia will suffer financially and lose its reputation as a business partner. If Russia were to pass this ban, it could be interpreted as payback for the US going into Syria. Russia also plans to start launches in late 2015, which means that  they are going to be selling their rocket engines elsewhere. However, in the 1990’s Russia agreed not only to sell unique engines to the US, but also to provide the US with full documentation on the engines’ design specifications.
Sources:
“Russian rocket engine export ban could halt US space program,” RT, September 12, 2013, http://rt.com/news/russian-rocket-engine-ban-039/
Cody Muzio “Export ban could harm ULA,” Decatur Daily, September 04, 2013, http://www.decaturdaily.com/news/local/article_1238c130-1515-11e3-8132-0019bb30f31a.html
Student Researchers: Victoria Arrington, Jasmine Aguilera, Wyatt Vaughn, Emily Koehn, Roman Jennings, Jordan Hinton, Paulo Silva (Santa Rosa Junior College)
Faculty Evaluator: Susan Rahman (Santa Rosa Junior College)