United States v. Laureys, 653 F.3d 27 (D.C. Cir. 2011):

"Generally an error is plain if it contradicts circuit or Supreme Court precedent." In re Sealed Case, 573 F.3d 844, 851, 387 U.S. App. D.C. 375 (D.C. Cir. 2009). The district court's instructions contradicted no precedents of this Court or the Supreme Court. Rarely do we find an error to be plain where "this court has not ruled on the question." United States v. Thomas, 896 F.2d 589, 591, 283 U.S. App. D.C. 62 (D.C. Cir. 1990). As the dissent has aptly pointed out in another context, "issues of first impression present plain error only when they tread upon 'a well-established constitutional or legal principle.'" United States v. Burroughs, 613 F.3d 233, 248, 392 U.S. App. D.C. 68 (D.C. Cir. 2010) (Brown, J., dissenting) (quoting United States v. Blackwell, 694 F.2d 1325, 1342, 224 U.S. App. D.C. 350 (D.C. Cir. 1982)).