Toward a Christian Theory of Swearing

I tend to mind my own business in public -- that is, until someone decides to start using obscenities around my kids, at which time I enter confrontational mode, motivated by the worthiest of causes.  But is my cause worthy?  What's the problem with swearing?  And if it's not OK for kids, why is it OK for adults?  My evangelical sensibilities bristle even when I hear folks swear in an adults-only context, especially when it's done by fellow followers of Christ.  In this regard, check out Joe Carter's long overdue "Christian Critique of Swearing."

Certainly my sensitivity has dulled over the years since a childhood when I would equate a stray four-letter word with a greased chute to Hell (especially since one of the coolest Christians alive does it), but the question persists: is it OK for Christians to swear?  Is opposition to swearing tied up in a legalistic approach to faith?  Should the ongoing cultural engagement project challenge the rapidly loosening standards of proper speech in our public life? 

Rob