The rule of lenity is something you should have in the toolbox regardless of being a trial or appellate counsel.
Intisar A. Rabb, The Appellate Rule of Lenity: Responding to Abbe R. Gluck & Richard A. Posner, Statutory Interpretation on the Bench: A Survey of Forty-Two Judges on the Federal Courts of Appeals. 131 HARV. L. REV. F. 179 (2018).
Lenity’s prominence is unsurprising for a few reasons. First, as an ancient principle directing judges to construe ambiguous criminal statutes narrowly, SeeAntonin Scalia, A Matter of Interpretation 29 (Amy Gutmann ed., 1997) (“The rule of lenity is almost as old as the common law itself, so I suppose that is validated by sheer antiquity.”
Justice Scalia and Professor Bryan Garner have helped elevate the rule of lenity by including it in a set of fifty-seven recommended canons of construction in their widely read treatise on interpretation.