How far should public decision-making go?

Lately, there have been a plethora of efforts and initiatives to engage citizens and members of the public in consultation, deliberation, and decision making concerning public policy, land-use, community plans, and even government budgeting.  Municipalities, non-profit organizations, and private enterprises are increasingly undertaking public consultative efforts of this kind.  However, a central question facing any public initiative is how much of the final decision-making should rest in the hands of citizens and members of the public. 

This question is especially acute in the public realm.  If elected officials are meant to be accountable for public decision-making, but opt to undertake public consultation in an effort to engage citizens, how much of the final decision-making should they delegate to participants in the public process?  If they delegate all decision-making, how, or who, can be held accountable for the final course of action?  On the flipside, to what extent can we reasonably expect citizens to be engaged and interested in public consultation if they will have no say in the eventual policy direction or the final decision? 

This is bound to remain a perennial question, with different answers depending on the context.  It may be useful to focus on the desired outcome of public consultation.  If the goal of a consultative process is to achieve a final decision that reflects public opinion, then perhaps elected officials, government or organizational staff could be given wide berth to utilize a range of engagement tools to gauge public feedback such as polls, town halls, online forums, or surveys.  The vested authorities could retain final decision-making over the eventual course of action. 

If, on the other hand, the goal is to engage the public in a genuinely democratic process, whereby each person should be given an equal opportunity to influence, and select, the final decision, then strict adherence to a set of guiding principles, and a final vote, may be more appropriate.  Full delegation of power to the public participants would be necessary from this perspective.

Somewhere between these two possibilities lies the notion that the goal may be, instead, to engage a range of people with different backgrounds, interests, and resources, in a deliberation about a selected topic, in order to produce new understanding, and or new knowledge regarding an issue of public interest.  From this standpoint, perhaps there should be no expectation of final decision making for any party involved.  

What do you think?  When should decision making power be fully delegated to members of the public?  For something like the removal of the Georgia street viaducts, should the public be allowed to make the final decision, or should public officials solicit public feedback in order to inform their own decision?