federalevidence.com reports on:
In trial for mail fraud and theft from a program receiving federal funds, trial court error in permitting the prosecutor to cross-examine the defendant state legislator as to her opinion of whether other witnesses were lying and lacked veracity, however error did not rise to plain error; joining consensus of six other circuits on the impropriety of requiring a defendant to testify as to the veracity of other witnesses, in United States v. Schmitz, __ F.3d __ (11th Cir. March 4, 2011) (No. 09-14452)
The Eleventh Circuit joined the First, Second, Third, Fifth, Seventh, and Ninth Circuits in finding that a prosecutor’s questions on cross-examinaton of the defendant as to whether other witnesses — specifically those telling a different story than the defendant — are lying. The reasons for this limit on cross-examination are diverse, but carefully explained in a recent case by the Eleventh Circuit.
Be advised this is already the rule in courts-martial. It is improper to ask an accused if other witnesses against him are lying. From my Trial Notebook (Beware: needs “Sheperdizing).
United States v. Jenkins, 54 M.J. 12 (C.A.A.F. 2000)(Court consistently held that a witness may not opine that another witness is lying or telling the truth. The Court of Appeals for the Armed Forces has adopted the rule followed in the federal circuits that have decided the issue that “prosecutorial cross-examination which compels a defendant to state that law enforcement officers lied in their testimony is improper." And see United States v. Marrie, 43 M.J. 35 (C.A.A.F. 1995).