Richard Rambaran obtained federal habeas relief after his Florida trial used a standard manslaughter instruction later recognized as legally erroneous. The State appealed, arguing that counsel was not ineffective for failing to anticipate the developing state-law rule and that the error had not been preserved. The Eleventh Circuit reviewed the sequence of Florida appellate decisions, including the later decision treating the instruction as fundamental error, and the timing of Rambaran’s still-pending direct appeal. The court held that the state court’s rejection of Rambaran’s ineffective-assistance claim was unreasonable under the federal habeas standard. Counsel failed to raise the instruction issue while the direct appeal remained open, and the subsequent legal development meant that the omission deprived Rambaran of the opportunity to obtain the benefit of the governing rule. The court rejected the State’s argument that counsel had to predict future law in every case but concluded that this unusual procedural timeline made the omission constitutionally significant. The court reversed the judgment denying habeas relief.