My preference is for the parliamentary model.
I do not believe that the primary face of the group should be vested heavily or solely in a single person. This is an international group, and to be representative, it needs to be explicitly collegiate. My mental model of operation of the elected committee is one in which most communiques are delivered from the committee on behalf of the group. If we note how the group has operated in the past, and think about how it might operate in the future, I suspect that most communications will be electronic, via the web page and via social media. This is of course in addition to any publication we do. Applications for funding etc., might go out under the hand of the Chairperson, but this would be on behalf of the committee and would probably be drafted collectively.
As I see it, the primary role of the Chairperson is to coordinate and manage the committee, and to break deadlocks. This is in contrast to the American Presidential style of executive office, where the President wields immense power and really does have executive authority. The parliamentary model, on the other hand, places responsibility and authority in the committee as a whole. The model of leadership in this model is by influence, rather than position. Because the authority is vested in the committee as a whole, the fate of the group is less influenced by the personality and behaviour of any single person.
As Frank observed, another strength of this model is that the elected team sort out their roles among themselves, so that the Chairperson has the support of the majority of the elected committee members. Of course the elected Chair may not have the support of all of the elected members, but this situation could arise equally (or even more probably) in the situation where the Chair is elected directly.
I agree with Frank, that we would have to have a fifth person on the committee in order to make the system work. I think that is reasonable and even desirable given our geographical and cultural diversity. It also makes the committee better able to handle one person being out of commission. This seems reasonable, irrespective of the mode of electing the Chairperson.
The role of Secretary could be split from Treasurer. Communications is now more important in small groups than Secretary, and generally has a more marketing brief.
Please don’t feel shy. Let’s hear your thoughts.