The issue of whether and when it is okay or even necessary to break of relationships has been raised here before—most often in the context of unrepented and therefore ongoing wrongdoing, where the victim decides that the only way to protect himself from further injury is to stop interacting with the offender. (Click here for Katie's latest post on the topic.)
But concrete wrong isn't the only cause of friendship dissolution. I've just finished reading a chapter on "The Parting of Ways" in von Hildebrand's just-published memoir, My Battle Against Hitler, which brings out a very different case. The breach in friendship is here not caused by one friend commiting a wrong against the other, but by the opening of an unbridgable "value gap" between them. People who had thought of themselves as friends, as having similar interests and harmonious personalities, may all of a sudden find themselves irreconcilably opposed on a very basic level. Speaking about the historical situation in Germany and Austria during the rise of National Socialism in the 1930's, Hildebrand writes that
The present epoch is characterized by the fact that so many things once hidden are now being revealed: both the good and the bad in people, which has remained concealed from others (as well as from themselves), is now coming to light. Hidden and base passions, brutality, ruthless violence, fanatical resentment, unprincipled behavior, cowardice, intellectual confusion, and weakness, on the one hand, and heroism, kindness, strength of character, noble courage, unwavering intellectual clarity, and a deep, indestructible religiosity, on the other—all these qualities are being revealed in many persons in whom one might never have suspected their existence. All this makes for a fearful trial, leading inevitably to a decisive parting of ways among persons.
The break is not so much caused as made manifest. It reminds me of Luke 17:34-35: "I tell you, on that day there will be two people in one bed; one will be taken, the other left. And there will be two women grinding meal together; one will be taken, the other left."
In a much less dramatic and less final way, this sort of thing happens all the time. Political or philosophical differences, for instance, can be significant enough to make friendship very difficult. ("Agreeing to disagree," except in trivial things, is not as easy as it sounds. Nor is it always called for. Some issues are too important and dear to our hearts to be set aside.)
There's nothing wrong, it seems to me, with deciding that those friendships aren't worth the constant agravation they cause. Another instance is when the circumstances of life place former friends in such different positions and social spheres that their relationship becomes strained. Again, it may be better to let such friendships die a natural death than to attempt to keep them going or feel guilty about not maintaining them.
These ways of cutting ties are very different from the ones Katie mentioned in her previous posts, though also worth having in mind as we think through and discuss the principles of authentic community.