From Ioannes at Commentarius de Prognosticis:
"As has been repeatedly pointed out here, we serve in the best interests of the political, economic and social order when we as individual Christians take up our responsibility to feed the hungry, give drink to the thirsty, care for the sick, clothe the naked, visit the imprisoned, shelter the homeless and welcome the alien (Matthew 25:31-46). Everytime we abdicate our responsibility and evade our accountability as stewards of God's creation and as children in His Kingdom, on the one hand we elect politicians to produce a nanny government that in turn enslaves us to Caesar (the logical outcome of left's point of view), or we enable the growth of an unlimited market that would sell human flesh at any price (the logical outcome of the right's point of view). The Church's responsibility is to save souls, and we are members thereof. Let our light then shine by our good works. If we do that, then we obviate the need for either an unlimited nanny government or an unlimited laize faire market place. The Church has NO mission in the political, economic or social order."
I would just add, to drive home the point, the greatest periods of turmoil for the Church have always accompanied her direct involvement in the political world. The primary mission of the Church is to bring people to Christ, no more and no less. It has the secondary responsibility, which is still completely tied to its primary mission, to spread truth and the Gospel message around the world. Part of this duty does involve the Church in the political world because the political world is part of mans world. That being said, the role of the Church is one of consigliere, advising governments and political leaders in their roles as part of the body. The Church has a lot to say about the nature of the state and its proper function but it is not to involve itself directly in the state by means of assuming political positions or supporting political parties.
Of course, that hasn't stopped the American Bishops, through their group USCCB, which by the way is not an officially sanctioned church body, from becoming a wholly owned political action committee of the Democrat Party. And this has allowed Democrat Party politics to overcome and crush the truth inside the American Church.
If the Bishops would only listen to their own Church teachings and the truth what a difference it would make! But I suppose then they wouldn't get to hob-knob with the Kennedy's and Giuliani's of the world. They'd be stuck hanging out with a poor carpenter from Nazareth instead.