Public theology is a challenge for the church. Theology is essentially 'God-talk' and there are a number of difficulties that become obvious when engaging in 'God-talk' in the public domain. Firstly, not everyone believes in God and those that do may not believe in the same God that you do. Even within the Christian church this cannot be taken for granted. When we do public theology badly, we reinforce an image of a church that is outdated and irrelevant, only interested in making moral pronouncements on the rest of society (and too frequently ignoring the 'log' in our own eyes).
Very occasionally, healthy, intellectually engaging, genuine theological discussion emerges in the public arena. One of the reasons that I'm a big fan of the TV show, The West Wing, is the way that religous topics are handled. The episode "Take This Sabbath Day" explores some of the political and religious dimensions of the death penalty. The show's creator, Aaron Sorkin, consulted with a priest, a rabbi, a Quaker and a Baptist minister while working on the episode. Here's a snapshot from one scene:
Toby: The Torah doesn’t prohibit capital punishment.
Toby: It says, ‘An eye for an eye’.
Rabbi: You know what it also says? It says a rebellious child can be brought to the city gates and stoned to death. It says homosexuality is an abomination and punishable by death. It says men can be polygamous and slavery is acceptable. For all I know, that thinking reflected the best wisdom of its time, but it’s just plain wrong by any modern standard. Society has a right to protect itself, but it doesn’t have a right to be vengeful. It has a right to punish, but it doesn’t have a right to kill.
That's the kind of honest, public theology that I think we could have more of.