IF .....Costner was a driving force behind the making of this film.....
then I'll forgive him first billing, with a character who may or may not have played such a central role as depicted in this film.
Perhaps his name was required (sadly) to draw people to see what should have been a fascinating film anyway.
It is clear to me that the actual "main" characters are Greenwood's JFK and Culp's RFK.
If you knew nothing about this crisis previously, then this film would give you a pretty good idea of how it played out from the American government's perspective.
Scary !!
( Kudos to all concerned that they - apparently - tried to stick close to the known facts and DID NOT try and make a Michael Bay style Pearl Harbor romantic drama out of it. )