He said the taoiseach should have the same privilege as if he were a party in the High Court, litigation privilege over the advice was sought in response to an allegation, and legal privilege over all the correspondence.

BBC: Ahern begins tribunal challenge

An attorney for Mr. Marsch confirmed that at one point Mr. Marsch did hire Mr. Minkow's firm to obtain information about wrongdoing at the company, but also said that the findings detailed in Mr. Minkow's report were protected speech covered by a litigation privilege, and that Lennar's libel suit was frivolous.

WSJ: Minkow to Plead Guilty in Lennar Insider-Trading Case

Having lawyers hire accountants can bootstrap attorney-client privilege to accountant communications, which makes sense where tax litigation is imminent or might involve an IRS criminal matter.

FORBES: What To Give IRS In An Audit

Ms. TASIA SCOLINOS (Spokesperson, Justice Department): And if the agency head determines that disclosure of that information would cause harm to the country, the Justice Department would review the proposed state secrets privilege claim and determine whether its assertion is appropriate in the litigation.

NPR: NSA Operations Remain Opaque to Investigators

Traditionally, documents to be used in tax litigation and relating to the strength or weakness of a tax position are covered by work-product privilege so the IRS generally cannot get them.

FORBES: What To Give IRS In An Audit

Attorney-client privilege protects communications between clients and their lawyers, whether or not those communications deal with anticipated litigation.

FORBES: What To Give IRS In An Audit