Without the background of a ongoing cold war with a rival superpower, could a Colossus be set in modern times?
It doesn't have to be a rival superpower. Just two computers linking and forming one massive, "all knowing" supercomputer would be enough to set things in motion. Especially with the way computer technology is today as compared with the 70s. The supercomputer could easily hack and enslave all the other computer systems in the world, thus taking control of very nuke regardless of country of origin.