William Leisner wrote:
However, it strikes me that a missile designed only to travel partway around the globe might not actually be able achieve orbit. Also, if I'm not mistaken, a nuclear missile is mostly missile, with a relatively small warhead.
You're thinking 20th century tech. Don't forget that missile was presumably built in the mid-21st century (during World War III). We can just say ICBM operate differently in that era.
Why would you presume such a thing? This was clearly an obsolete
missile that the US government gave/sold to Cochrane for his warp project, and not one of the most current generation of defenses against the threat of the Eastern Coalition. Not to mention that WWIII probably didn't last long enough for anything to be built during the conflict.