For many Christians, faith is fundamentally private and consists of their attending church, praying and being honest in their dealings with others. If Christianity touches on politics, it does so only obliquely by making the individual politician more virtuous as a person. This is not to be taken lightly, of course, and we can be grateful if more of our political leaders are upright people. But it does not address politics as politics, and it has no real implications for public policy. We shall at this point leave this approach behind, since I am persuaded that it represents a defective understanding of the faith and its all-encompassing claims.
Koyzis, Political Visions & Illusions: A Survey & Christian Critique of Contemporary Ideologies, Kindle loc 2307.