In the state of New York, it is a "matter of strategy and tactics which ultimately rests with defense counsel." This was determined last month in People v. Colville.
The issue arose from the murder trial of Delroy Colville. In that case, the defendant was charged with second degree murder. The defendant claimed self-defense.
The defense attorney wanted to give the jury instructions on two lesser included offenses: first and second degree manslaughter. However, the defendant opposed the instructions. Although the judge agreed with defense counsel, he followed the defendant's wishes and did not give the additional instructions to the jury.
The jury convicted the defendant and he appealed. The intermediate appellate division unanimously affirmed. However, the state high court overturned the conviction finding that "[b]y deferring to defendant, the judge denied him the expert judgment of counsel to which the Sixth Amendment entitles him."