The first definition of the transitive verb “infer” is: To conclude from evidence or premises. The political/rhetorical problem with the grammar here is that a transitive verb takes a direct object, i.e. Someone infers something. Donald Rumsfeld wants reporters to refrain from inferring anything about anything he might or might not say about connections between Iraq and al-Qaeda. The problem with this is, of course, that as language-using, rational animals we humans must infer. To suspend inference is to give up willingly one of evolution’s most potent human defense mechanisms. It also happens to be politically convenient for a defense secretary to suggest reporters do this unnatural (and unethical) thing.