A defendant is entitled to a jury instruction on an affirmative defense only where the defense theory is supported by substantial evidence. The court here considered the continued viability of the first prong of the disjunctive test articulated in People v. Sedeno (1974) 10 Cal.3d 703, which suggested that a defendant was entitled to an instruction on a defense on which the defendant was “relying,” even if no substantial evidence supported the instruction. The Third District concluded that more recent Supreme Court authority had overruled this portion of the Sedeno test. In this appeal the defendant argued that the trial court had erred prejudicially in failing to give a sua sponte instruction on the defendant’s burden of proof on his defense of withdrawal. The People argued that the defendant was not entitled to an instruction on the withdrawal defense because that defense was not supported by substantial evidence, so that any error in failing to instruct on the burden of proof was necessarily harmless. The Court of Appeal agreed with the People. Noting that the test for a withdrawal defense is an objective one, the court found that the lack of substantial evidence to show that the defendant communicated his withdrawal to the other parties involved in the offense or took any steps to prevent the crime was fatal to his ability to raise the defense.