Intelligence failure can begin with the wrong assumptions

Has any military intelligence system been more incompetent than Nazi Germany's?

Yes, but the Nazi case is complicated because British-controlled agents and disaffected officials made parts of the system effective for purposes its leaders did not understand.

The panel resists describing Nazi intelligence as simply useless because British-controlled agents often made the network perform effectively for British purposes. Some German intelligence officials were also less committed to the regime than their formal posts suggested. Late Roman and Napoleonic systems provide clearer examples of poor performance, while the US failure to anticipate Chinese intervention in Korea illustrates a different problem. Major powers can dismiss evidence when they assume smaller allies or partners will not act independently, turning political hubris into an intelligence blind spot. The Suez Crisis broadens that lesson to alliance management: coercing partners can buy immediate compliance while encouraging strategic independence or disengagement later.