John Marshall Harlan II

“ We reverse, and hold that the Government need make no showing of probable cause to suspect fraud unless the taxpayer raises a substantial question that judicial enforcement of the administrative summons would be an abusive use of the court's process, predicated on more than the fact of re-examination and the running of the statute of limitations on ordinary tax liability. ”

“ Nor does our reading of the statutes mean that under no circumstances may the court inquire into the underlying reasons for the examination. It is the court's process which is invoked to enforce the administrative summons and a court may not permit its process to be abused. [20] Such an abuse would take place if the summons had been issued for an improper purpose, such as to harass the taxpayer or to put pressure on him to settle a collateral dispute, or for any other purpose reflecting on the good faith of the particular investigation. ”

“ If a taxpayer has filed fraudulent returns, a tax liability exists without regard to any period of limitations. Section 7602 authorizes the Commissioner to investigate any such liability. [12] If, in order to determine the existence or nonexistence of fraud in the taxpayer's returns, information in the taxpayer's records is needed which is not already in the Commissioner's possession, we think the examination is not 'unnecessary' within the meaning of § 7605 (b) . ”