From publisher blurb:
Project Watchtower is a semi-secret government program whose stated goal was the control and supervision of America's rapidly growing Mutant population. When the program was instituted in 1953, ‘controlling' mutants meant extermination, and for generations of America mutants, the grimly iconic "Watchmen" mecha have been harbingers of death. Project Watchtower predates the creation of Psi-Watch by several years, and the two government agencies have worked at cross purposes at several points. Project Watchtower has the brainchild of FBI Director J. Edgar Hoover- plans for the program date back to the late 1940s, but Hoover lacked the funding and technological know-how to initiate the black program until decades later.
The first Watchman mecha came on line in 1962. Prior to that, the agency used well armed, FBI-trained mutant hunters to capture or kill mutants. As to be expected, casualties were high, as the hunted mutants fought hard for their lives, slaughtering dozens of FBI-affiliated hunters. Hoover's towering mechanical warriors were a welcome substitute, and quickly became the most potent weapon in the pure-human arsenal. Upgraded dozens of times over the years, the Watchman series of mecha have included several similar units of gigantic mutant hunters, as well as smaller, more efficient experimental models.
Psi-Watch itself opposed Project Watchtower since its inception, arguing that Mutants make excellent operatives and that hunting the species en masse only breeds more Mutant terrorists. Despite Psi-Watch's objection, and despite several black operations against Project Watchtower itself, Hoover was able to keep his robotic army in service. By the late 1960s, the large scale Mutant purges of the intolerant 1950s had ended, and Watchman robots were only publically deployed to combat Mutant riots in the inner cities. Well connected, ultra-wealthy Mutant hunters (especially the close friends of Hoover) occasionally ‘rented' a Watchman mecha as a bodyguard of sorts when they ventured into America's ghettos to slaughter the genetically unfashionable.
Project Watchtower was officially ended by Jimmy Carter in 1979, but by that time its technology had fallen into the hands of various interests. The Republic of Cebary fields advanced versions of Project Watchtower's creations, using them to police its enormous slave-Mutant population. The technology has made its way into the open market, becoming almost obsequious. China uses modified Watchmen mecha to maintain internal security, Al Queda uses jury-rigged versions of the robots to carry out terror strikes, while Humanity's Sweat uses the massive war machines for their original purpose: the eradication of the Mutant threat, wherever it may hide.
This sixteen page sourcebook for the Psi-Watch Campaign setting details Watchtower Mecah units, rules for them gaining sentience, as well as Bio-Guardians and an alternat timeline that introduces Grendel Generation Technology.