Political involvement

From the National Post:

On Thursday, the Vatican will release new instructions for Catholic politicians to oppose same-sex marriage, which has already been adopted in Belgium and the Netherlands… The document builds on the Pope’s approved guidelines for politicians, issued last January, calling on them to oppose abortion, euthanasia and same-sex marriage.

Interesting development. Seems to me that we (I) need a better understanding of appropriate political involvement for Christ-followers. We don’t live in a Christian country, and it’s not always appropriate to impose Christian beliefs on everyone. But is it ever appropriate? If not with this issue, what about with war? Euthanasia? What if I was a Christ-follower in Nazi Germany? I have more questions than answers.