In most cases, there's nobody in the group who is qualified to be the leader. All memebers have equal rights to decide and judge. The best you can do is to propose and recommend, which is nearest to being the leader. It is the case at least from my past experiences. Could Mr ChenXing amplify his answer? I'm very interested in the discussion of this problem, in part because it involves decision making process and probably in exams of CS2250!
By the way, Mr ChenXing's idea is very similar to Vroom-Yetton Model of decision making process. Are you referring to that model?
Many thanks.