United States v. Supreme Court of New Mexico

Issue: Whether the U.S. Court of Appeals for the 10th Circuit erred in holding that New Mexico Rule of Professional Conduct 16-308(E)—which states that a prosecutor shall not “subpoena a lawyer in a grand jury or other criminal proceeding to present evidence about a past or present clients unless the prosecutor reasonably believes,” among other things, that “the evidence sought is essential to the successful completion of an ongoing investigation or prosecution” and that “there is no other feasible alternative to obtain the information”—may be applied to federal prosecutors serving subpoenas outside the grand jury context.