Mixing Faith & Politics?

Something I have been thinking about for several months (since I read Blue Like Jazz), is "how much should we mix Faith & Politics?". The basis for this question was my realization from BLJ that Conservative Christians are are driving away people through their politics. They are seen as anti-gay rights, anti-choice, anti-environment and then worst of all they get affiliated with blue blood Republicans as being pro-war and pro-big business!

In my missions classes in college something that is driven into your head is that when you go as a missionary to a foreign culture you are there to represent Christ not your culture. In other words you are to share the gospel and the gospel only. Like Paul, missionaries are to preach nothing except Christ crucified. Now really this is impossible to do completely because we are all products of our culture, it is woven into us and we can not separate ourselves from it 100%. Missionaries must do their best in this endeavor though so that if someone rejects Jesus it is truly Him they are rejecting, not the missionary, not the sending culture. Vice-versa, you do not want someone accepting more than just Jesus. The goal is to evangelize the Gospel of Jesus to people on a heart level that means something to them where they are at now, nothing more and nothing less. So no preaching capitalism or democracy or free trade or Communion should go before the sermon and you need to have a piano or organ for worship... certainly NO drums!

God forbid that I or my culture embedded in me should ever be the reason that anyone rejects Him!!! The Cross itself is naturally offensive (a stumbling block to the Jews and foolishness to the Gentiles, 1 Cor. 2) and doesn't need any help from me to be rejected. Who wants a God that lived a short life as a dirty little poor human only to die a disgraceful death on a cross as a common criminal. That is highly offensive and pure idiocy in itself!

I have more to say on this, but to keep this from turning into a book and nobody bothering to read it, I will end on these last few questions and post more on it later... if the above philosophy is good for missionaries, why not for those of us at home trying to evangelize our own fallen nation? Are we preaching more than "Christ Crucified"? Have we become the stumbling block rather than the cross?