The Roman Catholic Archbishop of Detroit recently said that pro-marriage-equality Catholics should not present themselves for Communion. Writing in the HuffPo, Charles Reid takes him on.
....[O]n matters of divorce, contraception, and even in vitro fertilization, Catholics have reached a modus vivendi with the larger secular society. Catholics truly believe in the indissolubility of marriage. That, for Catholics, is what makes marriage sacred. And even while most Catholics practice contraception at some point in their lives, they also, most of them anyway, acknowledge that opposition to contraception is part of their Church's teaching. Same goes for in vitro fertilization. Most Catholics appreciate the moral dilemmas posed by this practice. But Catholics by and large do not try to outlaw these practices as a matter of secular law, nor do bishops try to use Communion as a means of enforcing this sort of political agenda.
If the Catholic Church and secular society can achieve co-existence on these points, why not on marriage equality? If a Catholic can believe that a secular divorce law is allowable, even though it is opposed to an essential property of marriage, how is that different from a Catholic who believes that secular law should adopt marriage equality, even if it does not conform to the Catholic understanding of marriage?
What this line of questioning is really calling for is a searching re-examination by Catholic thinkers of Church/State and Church/Society relations. What does it mean for the Catholic Church to exist in a world that is authentically pluralistic?