Pretty sure he's talking about the potential for Russia dropping nuclear bombs on every major city on Earth.
Besides, a nuclear attack would already be covered under the much larger war mentioned, which is something that was deemed less concerning.
The direct damage would be massive but not civilization-destroying.
Also, Russia's rockets still seem to be working pretty well as evidenced by the fact that they were used to send American astronauts to space for the last 10 years[1].
[1] https://en.wikipedia.org/wiki/Soyuz_(rocket_family)#ISS_crew...