Ted
As society and the problems that face it become more and more complex, and as machine become more and more intelligent, people will let machines make more and more of their decisions for them. Simply because machine-made decisions will bring better results than man-made ones. Eventually a stage may be reached at which the decisions necessary to keep this system running will be so complex that human beings will be incapable of making them intelligently. At that stage the machines will be in effective control. People wont be able to just turn the machines off because they will be so dependent on them that turning them off will amount to suicide.