What is the test for a defense counsel to ask to testify as an advocate while continuing to act as a witness?

Latimer's request to testify while continuing to act as an advocate, the denial of which was the basis for this argument on appeal by counsel, ran directly contrary to the advocate-witness rule. Appellate counsel testified in the district court that she raised the request because she thought it fell within "the exception" to the advocate-witness rule. Tr. 23. "The case law... noted that the requested testimony might be allowed in those instances where counsel was the only person who can testify to that particular matter." Tr. 22. But an advocate's exclusive knowledge of facts material to the trial is not listed as such an exception in DR 5-101(B). And the New York case law relied upon by appellate counsel in pursuing the state-court appeal does not establish such an exception.⁸ See People v. Baldi, 54 N.Y.2d 137, 148-49 & n. 1, 444 N.Y.S.2d 893, 429 N.E.2d 400, 406 & n. 1 (1981) (concluding that defense counsel was not constitutionally ineffective for, inter alia, testifying on behalf of client where doing so "strengthened the insanity defense").⁹

[601 F.3d 76]