The current crisis in the Ukraine brings with it the real prospect of a rift between the United States and her allies on the one hand and Russia on the other. That in turn could threaten American access to space since currently the Russian Soyuz is the only spacecraft that brings astronauts to and from the International Space Station.
Writing for NBC, Jim Oberg, in a March 3, 2014 article suggests a plan to try to change that situation.
First, Oberg suggests retrofitting a SpaceX Dragon to be a crew rescue vehicle, to be docked to the ISS in the event the space facility has to be evacuated. This would allow an extension of tour times for the crews of up to a year, buying some time.
Next, he points out that the Chinese have their own spacecraft, the Shenzhou, that could be used to take astronauts up to the ISS. There are some political hurdles to doing that. It would certainly mean that China would have to become a full space station partner. China, like Russia, is a human rights abuser and has exhibited imperialist tendencies, primarily to the South China and East China Seas. Taking on China might mean that the ISS would have two rogue nations rather than just one involved in its operation.
Finally the commercial crew options need to be accelerated as quick as possible. A great deal of work needs to be done getting the SpaceX Dragon human rated, along with the Boeing CST-100 and the Sierra Nevada Dreamchaser. Currently commercial crew vehicles are scheduled to fly in 2017. How quickly the process of getting one or more of these vehicles operational and how much money it might costs are, as of this writing, unknown.