The U.S. Catholic bishops offer four principles that should guide our faithful political engagement:

1. As an institution we are called to be political but not partisan. The Church cannot be a chaplain for any one party or cheerleader for any candidate. Our cause is the protection of the weak and vulnerable and defense of human life and dignity, not a particular party or candidate.

2. The Church is called to be principled but not ideological. We cannot compromise our basic values of teaching, but we should be open to different ways to advance them.

3. We are called to be clear but also civil. A Church that advocates justice and charity must practice these virtues in public life. We should be clear about our principles and priorities without impugning motives or name-calling.

4. The Church is called to be engaged but not used. We welcome dialogues with political leaders and candidates, seeking to engage and persuade public officials. But we must be sure that events and photo ops are not substitutes for work on policies that reflect our values.

taken from The Great Awakening: Reviving Faith and Politics in a Post-Religious Right America by Jim Wallis