Do parties need leaders?

The Green Party has thus far survived while eschewing the whole idea of having a leader, instead they had principle speakers, the whole of whom it is to promote party policy on a national stage (cynics may say just like any member of a party's front bench). Currently their principle speakers are Caroline Lucas MEP and political economist Dr David Wall, both gain significant media coverage and, in many ways, act as leaders if only appearing as focal points. However underpinning the notion of principle speakers was the notion that there was no one leader but it was a movement and the speakers spoke on behalf of that movement; in themselves they did not decide policy, nor were they seeking any form of self aggrandisement.

On her campaign website Carline Lucas argues that "The election of a leadership team offers us new and exciting opportunities to take the radical message of Green politics into the mainstream". Fair enough, they have been mocked for not having a leader in the media; perhaps it is a sign of them evolving into a political party as opposed to a movement; having a leader is professional, it shows organisation. But is it really necessary? Are they better of with the principle of speakers standing on the shoulders of a movement they represent? I guess it raises the question of the role of the leader, are they the navigator, the rudder, or simple the representative. Tradition tells us the leader is the navigator the plots the political course of the party, in the words of US President Harry Truman "A leader is a man [person] who has the ability to get other people to do what they don't want to do and like it"; this certainly is the role assumed by Blair and Cameron, the successful reforming party leaders of recent years, but is the Green Party ready to be led? The man who Lucas supports to be her deputy, and who in turn supports her for leader, Adrian Ramsay, thinks the party do want a 'leader' and it is Lucas' "extraordinary abilities and expertise" that make her the best choice. While I agree she would make a great leader, is the the start of the shift away from a movement and towards being something the Greens are not actually comfortable with being: a professional electoral party?