At Mirror of Justice, Greg Sisk with an extended post on what Benedict has to say about the role of the Church in public life:

In emphasizing the proper role of the Church in the awakening and formation of conscience, while insisting the the Church must not enter into the “political battle” that remains instead the separate vocation of the laity, Pope Benedict XVI’s words have been portrayed by some as a departure from the public witness of his predecessor. After all, John Paul II addressed civil authorities regularly with boldness and spoke with prophetic directness on issues of human rights, pointedly including the sanctity of human life from conception to natural death.

I submit that these observers both have misread Benedict XVI as foreshadowing something of a withdrawal by the Church on direct engagement with civil regimes on basic matters of human rights (including sanctity of life issues) and have misunderstood the non-political nature of John Paul II in his forthrightly religious witness in the public square. In other words, I see in his first encyclical a steady continuity by Benedict XVI with John Paul II in the understanding of the appropriate role of the Catholic Church when it encounters the temporal civil order. John Paul II confronted tyranny in many areas of the world and the self-centered idolatries in our corner of the globe by speaking the truth plainly and by encouraging an evangelical spirit that would transform societies by first bringing spiritual renewal to the people. But John Paul II eschewed direct political involvement by the Church or its clery, particularly that of a partisan nature.

The priority of evangelical renewal in John Paul II’s messages was often overlooked, given the uncompromising power of his words regarding the sanctity of human life and the greater specificity of his teachings on the fundamental duty of civil society to protect human life and dignity (e.g., Evangelium Vitae). However, one should not extrapolate a general political agenda, much less a call for direct Church involvement in political campaigns or ideological platforms, from the Church’s teachings condemning such inherent evils as genocide, slavery, and abortion.