Role of elected representatives

Over the past several days, I've heard Thom Hartmann on Air America Radio, express the view that the role of elected representatives, such as Senators and Congressmen, is to vote the views of their constituents, even if this differs from their own personal views. While I can see some positive elements to this argument, I think fundamentally I disagree with it. Yes, I think our elected representatives have an obligation to listen to what their constituents have to say (and not just the rich and powerful ones), but I think their fundamental role is to lead, not follow. It is they, it seems to me, that have the obligation to consider and evaluate policy issues, reach some conclusion as to what the best solution may be (both taking account of the reasonable views and the unique needs of their constituents), and then use their persuasive powers to convince their constituents to follow in their lead. But, when their own best judgment conflicts with that of their constituents as expressed, for example, in a poll, I think they have an obligation to vote their own best judgment, taking into account the fact that this may harm their re-election chances. Otherwise, it seems to me, we would have something more like government by referendum, and all you have to do is look at the mess California has gotten itself into by doing that.