There is a myth that has circulated throughout our culture for over a generation now to the effect that we must be vigilant to keep our public-policy debates free of all religious assumptions. Religion, we've been told over and over, has no place in our public conversation. It's all about the separation of Church and state, don't you know.
This myth does great harm to our civic life because it essentially undercuts the possibility that any position one takes on an issue will be grounded in anything more substantial than personal taste. Consider a controversial social issue like capital punishment and imagine two people, Joe and Carl, debating it. Joe says he's opposed to capital punishment, and Carl asks why. What does Joe say?
He may respond by insisting that it's wrong to kill people, but, if so, Carl can simply ask him why killing people is wrong. Ultimately, Joe is going to have to rest his opposition to capital punishment on something other than his own subjective preferences, but the only solid ground he could rest it on is a conviction that God forbids killing. In the naked public square, however, that option is forbidden. The most that anyone can give as a reason for their position on capital punishment, or any of the issues we debate, is that "I don't (or do) like it," but that's hardly a compelling reason why anyone else should agree.
In other words, in a public forum which has been scrubbed clean of all religious references all debate comes down to a dispute over personal tastes and feelings, and in such a debate no one has any more moral authority or insight than anyone else. There's no possibility of appeal to transcendent objective values which could help inform our decision-making.
Indeed, the only way to prevail in public disputes is by amassing on one's side enough people who share one's feelings that one has the political clout to impose them by law on those who don't. In a world in which God has been banished from political discourse we don't win debates by persuasion, we win them by coercion. The person who can shout the loudest or who can gather the biggest mob is the victor.
Genuine public debates can only be carried out among people who share a common value system. If everyone agrees that God disdains killing then we can debate whether there may be reasonable exceptions to that principle. But if we expel God from our civic and social life we have no basis even for thinking that killing of any sort is wrong and, that being so, there's no place to stand if we wish to argue that capital punishment, or torture, or abortion, or gay marriage, or anything else, is wrong.
The irony of this is that the only people who can engage each other in the public square, the only voices anyone should bother to heed, are those of people who share a common belief in God. The atheist is really irrelevant because all he's doing when he says that X is wrong is telling us that he doesn't like X, and that may be an interesting biographical tidbit but it's nothing to build a policy upon.
RLC