From In re Application of Chevron Corp., 2010 U.S. Dist. LEXIS 117679 (S.D.N.Y. Nov. 10, 2010):

II. Deposition of Adverse Counsel

"Courts have been . . . concerned about the burdens imposed on the adversary process when lawyers themselves have been the subject of discovery requests, and have resisted the idea that lawyers should routinely be subject to broad discovery." [In re Subpoena Issued to Dennis Friedman, 350 F.3d 65, 70 (2d Cir. 2003).] Despite that concern — which has been born also of a reluctance to intrude on the attorney-client relationship and a sense that depositions of adversary counsel are unseemly — our Circuit has adopted a "flexible approach" that affords district courts discretion to permit such discovery when appropriate rather than prohibiting or more severely restricting discovery of adverse counsel. Indeed, it has made clear that "the disfavor with . . . the practice of seeking discovery from adversary counsel is . . . not a talisman for the resolution of all controversies of [that] nature." Rather, district courts in such cases are to "consider[] all of the relevant facts and circumstances," including:

"[1] the need to depose the lawyer, [2] the lawyer's role in connection with the matter on which discovery is sought and in relation to the pending litigation, [3] the risk of encountering privilege and work-product issues, and [4] the extent of discovery already conducted."