I don't think its offense that has killed traditional religion. After all, the religious types have traditionally been one of the loudest political groups in the US. People willing to hold up signs with dead babies to send a political message don't appear to care about offending others.

I definitely see that Christianity is getting less-and-less relevant in the US (as it has been in most other Western nations), but it seems like patriotism is its replacement, the Constitution is the new Bible and the founding fathers are the new apostles.