Christ the King says that his kingdom is not of this world, but he also says to his disciples, “Go out into the world and preach the gospel.”

What is the proper relationship between Church and State? There are four models for the interaction between the civil authority.

1) The State Church: the civil authority enshrines the Christian Church as the established Church of the country. This started with the emperor Constantine and was evident throughout history in many societies. Sounds good for Christians, and it has certain benefits, but it usually ends in tears. The Church becomes corrupted by the wealth and power of the state and being established. Soon Christianity has become a watery, compromised religion. I doubt if this is what Jesus had in mind when he said his kingdom was not of this world.
2) The Church following the Culture: In this model Christians assume that they live in a Christian country and assume that the values and standards of their countrymen are Christian ones. The Christian Church does not have established status, but it is ruled by the prevailing trends of culture. This is radically the case in our present situation in America. The prevailing Protestant ecclesiology is essentially market forces Christianity–individualistic Christianity. The liberal denominations follow the culture on abortion, homosexuality, politics, feminism and contraception.
3.) The Church Against Culture: In this model the Christians declare the prevailing culture to belong to the devil and withdraw. The Desert Fathers were the first Christians to do this once Christianity became the official religion of the Roman Empire. Many other Christian groups have done the same–various monastic movements, the Puritans in New England, various Protestant sects–the Amish, Mennonites, etc. This seems attractive, and it is the right option to those called to an enclosed monastic life, but as a model for the whole church it abdicates responsibility.
4.) The Church as Subversive Force: This fourth model is the one which is truest to the gospel for the whole church. We are to be in the world, but not of the world. We are there to bless what is good in our culture, and criticize what is bad. We are meant to be the prophetic voice against sin, but also the priestly voice of blessing when something is good. We are meant to be the salt of the earth, the yeast in the  dough, the city set on a hill.
In our present culture, one of the many tasks we have is to clarify for the American people just what it means to be involved as loyal Americans and loyal Catholics. As clergy it is our duty to be involved in the public square, and to speak out. We will not be silent on abortion, the torture of prisoners, unjust war, oppression of the poor, and a whole range of moral issues. Outside of election times, we have the liberty to name names and discuss individual politicians. We simply cannot do so in any way that would influence voters specifically, or to sway elections.
We must understand exactly what the separation of Church and State really is. It means we do not have a European style established Church. That’s it. What it doesn’t mean is that America should be an atheistic, materialistic republic.  It does not mean that church leaders may not speak out on matters of the public concern. It does not mean that church leaders are to be silent. The separation of Church and State along with the freedom of religion and freedom of speech enshrines the freedom to speak out and to bless what is good in our society and criticize what is evil. It allows the Church to act as a proper check and balance in our whole culture.
Finally, there are proper limitations on what clergy and official church documents may do. This limitation is not only in US civil law, but in Catholic canon law. Bishops priests and deacons are to build up the Kingdom of Christ–a kingdom that is not of this world. We are rightly limited in our political involvement.
However, while clergy and the Catholic Church as an organization is limited, individual Catholics are not. It is the job of the laity to be fully involved in the pro life battle. Lay people can and must speak out specifically and forcefully. They must be fully involved in the political process. They must work not only to have abortion banned, but until then to have abortion restricted. They must also work tirelessly to promote all pro life initiatives–programs for women in crisis pregnancies, programs to help them keep their babies, programs to promote fostering and adoption, programs that address the underlying philosophical, cultural and moral understanding of life.
This is the work of the whole Catholic Church–not just bishops, priests and deacons.
Get busy!