I recently posted a link to an essay by Scott Berkun a consultant and author of The Art of Project Management O'Reilly - 2005.
Entitled Why Smart people Defend Bad Ideas, it explained how allowing smart people to control the agenda can cause more problems than they solve. He explains how, obviously, smart people are quite good at fighting their corner and can push through and support bad ideas.
I thought about my experiences with this one at the time which, being not too smart at all, are quite common and broadly accepted his assertion that being trumped by an extremely quick thinking individual causes many people to stand aside and let the nonsense get implemented just because Dr know-it-all says it is the way to go.
That is not all there is to it however. In addition to avoiding a confrontation with a smart person whose reputation probably exceeds your own, there a desire to conform to the opinions of the group and accept that any direction is better than none and a whole raft of issues, many of which are explained here; Groupthink is a term that explains the process whereby a whole group can conform to what they believe to be the consensus and all undertake a process in which none of them believes.
This is not a triumph of compromise over dictatorship when there are far better courses of action available that have not even been discussed. Especially in a situation such as the one where one bright individual speaks out and instantly concludes a course of action that requires careful consideration. The choice of anyone that would gainsay that opinion is one of possibly causing confrontation and if they believe that the consensus of the group, especially the influential people in it, is in accord with that opinion then they will be likely to comply.
This leads to the worst of all worlds. The way to avoid this is to create a process where decisions are only ever made after due and careful consideration. The job of a Manager is to make decisions but also to find out the facts and opinions first. There needs to be a decision making process. Without it the decisions that are made are rarely the best.