"Sen. Frist backed off of his public accusation of perjury."

Do you think it is even vaguely possible that Frist backed off because of situation of it involving classified material, rather than the press spin of him backing from accusation of perjury. In other words the more prudent thing to do, is to first declassify the material, and only then to accuse of perjury. Otherwise there could be various consequences- for instance, Richard Clarke may be able to legally release his whole classified statement without first removing sensitive material; then the whole story shifts to the damaging information being released, and Frist being blamed for "forcing" Richard Clarke to release all of his statement.
Also the releasable portion could have enough blank out parts, that these blanked out parts, can be spun as being neccessary for "full meaning" of Richard Clarke statement [they could do a Davin: "The soul of meaning is not denotation. If you had any subtlety or depth to your thinking, you would know that. Meaning is not definitional." Or as Clinton said it depends on what your definition of "is" is. In other words evasion is a fairly easy tactic, especially if you throw in lots of "the glove doesn't fit" nonsense.]