The reasons being:
* Christian political parties send out all the wrong messages.
Setting up a party under the title “Christian” has the unfortunate effect of implying that there are no, or no ‘real’, Christians already in the mainstream parties, and/or that there are no opportunities for a Christian voice to be heard in the mainstream. Also it implies that Christians are a bloc of voters whose political views can all be represented by one single party. It implies then that this “Christian party” is the one which will be able to represent the views of all these Christians in the political system, in a way that other parties can’t. And it also implies that Christians who vote for other parties are somehow acting in a less Christian manner than if they vote for the party which claims to be Christian. Not one of these things is accurate, or helpful.
* Christian political parties are weakest where they need to be strongest
All Christians can agree on some moral and issues, which means it makes perfect sense to have Christian campaign groups and ongoing, informed Christian comment on social and political issues. But Christians are legitimately (even, rightly) divided on all the areas where a political party, in order to be successful as a political party, needs to have clear policies. Clear as in clearly articulated, and clear as in obviously following from a coherent and comprehensive political ideology. There is no such thing as a Christian policy on how often your bins should be collected, or speed limits, or rates of national insurance contributions, or when the troops should come home from Afghanistan. Of course you can and should bring Christian principles to bear on all these issues, but none of them constitutes an issue which it is the main business of the Church, or Christians, as such, to take to do with.
This is, maybe, only possibly principled, because here again, the opinions of Christians vary. But, o Scots and Scottish presbyterians, if you believe in the Establishment Principle, is it actually consistent to vote for a Christian political party? If you believe that the Church and the State have their own separate spheres, and that while they should co-operate in areas of mutual concern, they should not interfere in each other’s jurisdiction, does it make sense to vote for an organisation which intends, in effect, to give the Church an official role doing the State’s business within the State’s sphere? When the Church steps outside its role of (1st) preaching the gospel and administering the sacraments and (2nd) giving information to the State about its responsibilities before God, and starts in addition dabbling in matters civil, how is this any less of an encroachment than when the State presumes to tell the Church who is and isn’t fit to be ordained to ecclesiastical office? Maybe there isn’t really a conflict here, but somehow, the thought niggles.
After all, there isn’t actually a candidate standing in my constituency.
The concern of Christians is, of course, entirely understandable. In public life, expressions of Christian belief and manifestations of Christian practice are being more and more marginalised, more and more scandalous (to the secularist), more and more of an oddity. In this climate, the slim chance that power might be gained in the political system by a group which loudly proclaims its Christianity becomes fearfully attractive. But it’s not the Christian way. Christians need not feel in the least bit morally obliged to vote for a party simply because it has “Christian” in its title and casually flings around the name of the Saviour at every opportunity. Even a party which proclaims Christian moral values has to compete, among Christian voters, to win that X on the ballot paper which indicates the least worst option, and in the choice between workable policies derived from sub-optimal ideologies, versus a hodge-podge of populist pledges bolted on to lowest common denominator statements of moral values, Christians still need to exercise a bit of critical judgment.