Further investigation shows that "When it is not necessary to speak, it is necessary not to speak" is an old favorite of Fr. Neuhaus. (The formula goes back at least to Lucius Cary, 2nd Viscount Falkland, who used it in reference to change.)
Patrick Brennan of Mirror of Justice provides some context for Fr. Neuhaus's use of the maxim last Spring:
In Philadelphia in May to give the St. Thomas More Society's Gest Forum Lecture, Fr. Neuhaus was asked about what the U.S. Bishops had recently said about U.S. immigration policy. After some nice but uncharacteristic hemming and hawing, Neuhaus answered: "If it is not necessary for the Bishops to make a statement, it is necessary that they not." It's possible that Neuhaus qualified his principle in the colloquy that ensued (I was laughing too hard to hear everything), but, at least in substance, he meant it, and I think I agree with him, or pretty close to it.
I think one might well ask in what sense it is necessary that Catholic bishops not speak about justice for immigrants.
The late Paul Ramsey, a Methodist ethicist who taught for many years at Princeton, urged upon religious leaders certain "self-denying ordinances." One such ordinance is the Wittgensteinian-sounding rule that, on those things on which one cannot speak with authority, one should remain silent. Put differently: when it is not necessary to speak, it is necessary not to speak. This came to mind as I was reading another roundup of religious pronouncements on the war....
The idea is not that religious leaders should remain silent in a time of war. Far from it. Precisely as religious leaders, they should have a great deal to say that needs saying.... My point, in agreement with Paul Ramsey, is that the trouble begins when religious leaders abandon their presumed competence as theological and moral teachers in favor of political punditry and policy prescriptions. As individuals, they may of course express political opinions, which others may take for what they are worth. But any political statement that begins with "As religious leaders, we..." should be accompanied by a warning label indicating the probable abuse of religion.
And my point is that the trouble begins when religious followers abandon their presumed leaders in favor of political pundits, due to a too-neat classification of their leaders' statements into "doctrinal" and "non-doctrinal" subsets. The authority of the bishops is not the two-valued, on/off thing that some make it out to be.