This is a valuable argument to make, not just as a personal philosophical exercise, but also as a window on how we can all - believers in all different religious ideas as well as non-believers - construct and build on common ground in our efforts to live harmoniously alongside one another.
Until I can get to a more thorough review, let me share with you what I think is basically the core of the book - a quote from the first chapter ("Ethical Jazz"): (p31 - emphasis added)
Today, authority has to earn respect by the intrinsic value of what it says, not by the force of its imposition. There is a loss in this situation, of course, because power transitions are always dangerously unstable periods in human history, but there is unlikely to be a wholesale return to the past and its values unless we are overtaken by a mass religious movement that obliterates the radically plural nature of contemporary society. Barring that unlikely eventuality, we must do what we can to construct moral agreements that will have the authority of our reason and the discipline of our consent.