Since the last shuttle retired in 2011, US astronauts have been paying to ride to space on Russian rockets. According to recent news: BBC 16 September 2014 the earliest US launch is late 2017.
Currently politics of these two nations are having some differences of opinion. If the US suddenly found it impossible/impractical to use Russian transport to get to the ISS, could a US based astronaut launch occur sooner? Alternately could a ride be arranged with another nation like China?