So, I've Been Thinking...

Other than the obvious answer that it was Jesus' time and Scripture must be fulfilled...

If the Jewish judicial system couldn't give a death sentence (as only the Roman court could), why were the Pharisees allowed to crucify Jesus? Although Pilate washed his hands clean of their actions and petitions, why didn't he stop them from murdering Christ? Wouldn't the Pharisees, who are also under Roman law, be seen as attempting murder, and therefore, be arrested and tried for it?

But, maybe, the obvious is the only answer...