The conservative resistance to Pope Francis has circled its firing squad around Amoris Laetitia, the year-old apostolic exhortation that opens the door to communion for divorced and remarried Catholics.

A week ago, speakers at a conference in Rome accused the pope of heresy in the latest in a series of challenges, the most notable of which were the "doubts" (dubia) about Amoris issued by four cardinals last September. "The pope," declared Australian theologian Anna M. Silvas, “is a skandalon (scandal), the rock has become the stumbling block.”

To be sure, the other side has mounted a defense, but it's striking how little attention has been paid on either side to the theological concept that best supports the pope's opening -- and how ill-informed that attention has been.

The concept is oikonomia, Greek for household management (economy), and as developed by the Cappadocian fathers of the fourth century it expresses Christianity's profound insight into the flawed nature of humanity and the fallen condition of this world.

This provides the rationale for permitting second (and third) marriages in Eastern Orthodoxy. While affirming the Christian ideal of marriage as indissoluble, the Orthodox recognize that sometimes marriages become broken, and provide a path for the parties to remarry within the church in a ceremony that is penitential.

Likewise, oikonomia does not abandon the early Christian view that war is evil, but offers those who fight a penitential path to communion. In both cases, as in others, the point is that, in this world, it is sometimes necessary to do an evil thing in order to avoid a greater evil.

Roman Catholicism would rather divide wars into just and unjust and valorize the heroes of the former. Instead of allowing second marriages, it prefers to determine that a first marriage was not a real marriage by the fiction of annulment.

So on the right, the National Catholic Register waves away the Orthodox permission for second marriages as an artifact of Roman imperial law -- as if oikonomia were nothing more than a concession to the secular state. And Sandro Magister, the anti-Francis Vaticanista, asserts that second marriages are not sacramental in Orthodoxy, which is not the case.

Meanwhile, on the left, Cardinal Walter Kasper -- the prime mover behind the opening to the divorced and remarried -- shies away from embracing oikonomia while also claiming that the Orthodox do not consider the second marriage a sacrament. As for Pope Francis, he does not so much as mention oikonomia in Amoris.

Fifteen years ago, Creighton University's Michael G. Lawler made a strong case for Catholicism to embrace the principle of oikonomia when it came to marriage and divorce. More recently, Kevin Schembri of the University of Malta urged Catholics to learn from the Orthodox doctrine.

But oikonomia may just be too far outside Catholicism's comfort zone for that to happen. When you need white to be white and black to be black, accepting that this world sometimes requires us to do evil is an intolerable shade of gray.