Project Kingmaker was the secret Section 31 project to attempt to create and place powerful federation officers who would be able to push their agenda in public, whilst they secretly controlled them from the shadows.
During this project they began experimenting with Human Augmentation, resurrecting the ancient artificial eugenics research. During their development of Rex Semideum they created his genetic structure with the purpose of giving him extremely powerful telepathic and telekinetic abilities in addition to his Human Augment traits. After several failed attempts they eventually were successful in creating a viable embryo. However it was only after several attempts that they finally made one they were happy enough with to allow it to fully develop and be "born".
The result of the project were considered to be a total failure. As although they were successfully able to create a subject with the traits they required, they were unable to control the subject no matter how much indoctrination and control they applied. Eventually the project was written off and discontinued, until observations of the escaped subject revealed an exploitable weakness that could be used to control another subject.
The financial fallout of the project had a considerable effect upon Section 31's ability to act in the field. Forcing them to only gather intelligence via espionage for a long period of time, as their normal methods of bribing officials and making back room deals were out of their price range.