ACORN’s unavoidable problem, however, is that suing Fox News would give Fox — or any other media organization — the ultimate Christmas present: a legally enforceable way to compel ACORN to give up all its secrets.

The process by which a party to a lawsuit can force the opposing party to disclose information is called discovery, which can take the form of depositions, written questions, or demands for the production of documents. Under federal rules, a defendant can get court orders for discovery for any information relevant to its defense, except for privileged information such as attorney-client discussions.

If ACORN sues, it would have to sue alleging some variation of defamation or fraud. The problem is that for either allegation, truth is an absolute defense. Nothing could be more relevant to Fox establishing its defense of truth in the lawsuit than having access to ACORN’s office memos, emails, phone records, and bank statements. All of these would have a reasonable chance of providing evidence as to whether ACORN workers had knowledge of any of the topics seen on the videotapes.