Pascal-Emmanuel Gobry nails it:

To be a Christian is to believe that all political ideologies are suspect. And wrong. It doesn’t mean that Christians should retreat from all political ideologies — as that would also be a political ideology, and also wrong. By all means, be a Christian liberal. Be a Christian conservative. But if you are a Christian liberal, if you are a Christian conservative, then by definition there will be tensions between your Christianity and your political ideology. It’s axiomatic. And if you are a Christian first and an ideologue second, you should confront those tensions instead of papering over them.

The whole post is worth a read.