A Christian voice in Politics?

So why should I (we?) be involved in Politics as a Christian? I will try and give a short list here, which hopefully I can expand on and explain further in due course:

• As a voice for God in Society - As the prophets and judges were to Israel, so we should be today. God is concerned for Society as a whole and for his world (cf Genesis). As Christians we know that the world is fallen and sinful, and that it has been / will be redeemed. Even with this knowledge that what we do is never going to be enough to make 'as it is heaven, also on earth' we should still stand up for (our understanding of) God's views.
  
  
• As a voice for those without a voice - Jesus talks lots in his parables and teachings about standing up and speaking for those who are unable to do so for themselves. In the same way then, we should be standing up and speaking for justice and freedom from poverty, and being involved in both large scale campaigns to raise awareness, as well as being involved in in-depth discussions about the best and most godly ways to alleviate suffering and injustice.
  
  
• As a voice for God's people - Politicians should be (somewhat) representative of the people that they represent. Clearly then, a proportion of politicians should be Christian in order to ably represent the Christian population.
  

That's a start, although I'm sure that there are more that could be added in due course.