Where a racketeering act amounts to a substantive crime that carries a maximum penalty of life imprisonment, but a racketeering act that amounts to a conspiracy to commit that substantive crime does not, whether a defendant convicted of RICO conspiracy under 18 USC § 1962(d) is subject to enhanced sentencing under § 1963(a) based merely on jury finding that defendant agreed to join the RICO enterprise knowing that that members were conspiring to commit the racketeering act, or whether enhanced sentencing is permissible only upon a jury finding that includes a determination that the substantive racketeering act was actually committed?

Whether a defendant convicted of RICO conspiracy under 18 USC § 1962(d) is subject to enhanced sentencing under § 1963(a) based on a jury finding of agreement to join a RICO enterprise or only upon a jury finding that the substantive racketeering act was actually committed