Michele at Reformed Chicks Blabbing has written a very good article on the topic of Christianity, Politics and Blogging.   I've been trying to find a good "money quote" but the whole thing should be read to get the big picture.  Here's a good passage.
One final point about blogging. I think that visitors to this blog might want to look at it in a similar way to a Christian mommy blog or a Christian fishing blog, or Christian crafting blog, where the blogger shares their passion for their hobby or their vocation as well as their love of the Lord. Would you go to a mommy blog and complain that they aren't blogging enough about the kingdom of God if they are blogging about their children? Maybe not because motherhood is kingdom work, which leads me to my next point -- for the reformed all of life is about the kingdom. You can't really separate the kingdom from the believer. There is no such think as a secular anything for the Christian. It's all been sanctified by God and should be viewed from the perspective of his kingdom.
Or, we could add, a Christian gun blog.  Go read it if this kind of thing interests you.