Jesus Before Pilate

Once the Sanhedrin found Jesus guilty of blasphemy, why did this Jewish rabbi have to go to trial before the Roman authorities, namely Pilate?

Jesus had two trials, one Jewish and religious, the other Roman and secular. Rome reserved the right of execution in capital cases, so Jesus had to be handed over to the Roman authorities for execution. The Sanhedrin took Christ before Pilate. Jesus was then sent to Herod for yet another hearing (Luke 23:6–12) and then returned to Pilate for the final hearing and the sentencing (Luke 23:15–26).