Roberty, the Fair Tax without a prebate would certainly *work*, but the left would regard it as highly regressive (and rightfully so); there'd be no way to pass it.
I consider myself a classical liberal in the tradition of Locke and his successors on down through Hayek. As such, I believe a just society *is* obligated to care in some fashion for the least of us. My quarrel with the left is primarily over their means and methods. I believe that freedom, free association, free markets, and private charity are the best ways to help the poor, rather than our failed welfare state. That doesn't mean I think the poor should be abandoned to whatever demise fate would have in store for them.