We'll hear an overview of Proposition D, the ballot measure that would open the door to a half-cent sales tax increase if a list of fiscal reforms are met. Find out what a local economist says about the city's current tax structure and projections on how the tax increase would affect the current budget deficit. Finally, San Diego City Councilmembers Donna Frye and Carl DeMaio will debate the measure. You can join the discussion by participating in a live chat.