Those who are opposed to Cardinal Walter Kasper's proposal that some divorced and remarried Catholics be allowed to receive the Eucharist might want to reconsider whether the Church has been wise in allowing the widowed to remarry.
In their critique of Kasper's proposal, a group of American Dominicans points out that there was much disagreement in the early Church about whether widows and widowers should be allowed to remarry. Even many of those who believed they should be allowed to do so thought remarriage should at least be discouraged. But the case for not allowing an abandoned spouse to remarry is very similar to the case for not allowing the widow or widower to remarry—namely, that marriage is indissoluble, a sacramental figuration of Christ's covenant with his Church, a covenant not even death can dissolve. Can one think of another sacrament whose effects are supposed to be nullified by death? [For an obvious answer to this, see Fritz Bauerschmidt's comment below.]
Defenders of the Church's current practice demand that the abandoned spouse persevere in chastity. Why should the Church not demand the same of the widowed? Both are victims of a circumstance beyond their control. One possible response is that the dead never come back to life (or never come back to this life), whereas it is never impossible that someone who abandons his or her wife or husband may repent of it and seek reconciliation. This sort of thing has been known to happen, after all, and when it does, it's can be a profound evidence of grace. It's also exceedingly rare, especially when the unfaithful spouse goes on to have children with another partner.
Practically, then, the abandoned spouse is in the same position as the widow or widower: in both cases, chastity would seem to require heroic virtue. From very early in its history, the church decided not to demand such virtue of widows and widowers, despite its original preference that they not remarry. The question now is why it should demand such virtue of those whose first spouse is "dead to them," often through no fault of their own.
In a certain sense, of course, no one is ever dead to a spouse. A real relationship of some kind persists after estrangement, even after death. Catholics believe in a communion of the living and the dead, which is why a widower, remarried or not, may pray for the soul of his deceased wife. In just the same way, an abandoned wife may pray for a husband who has broken his marriage vows and started a family with someone else. The question is why the church should treat these two people—the widower and the abandoned spouse—so differently. If the early Church's rationale for (grudgingly) permitting widows and widowers to remarry is, in the words of a fourth-century canon quoted by the Dominicans, to make some allowance for "the arising of the fleshly spirit," then why shouldn't the Church be willing, for the same reason, to extend some kind of accommodation to the civilly remarried Catholic whose first spouse abandoned her long ago and is now no more a part of her earthly life than he would be if he were dead?
Did the early Church, in deciding to allow the widowed to remarry, "despair of chastity"? That is the charge that Kasper's Dominican critics level against his proposal. It is a serious one. I wish they would have taken its implications more seriously.