Who killed Jesus? A fashionable answer is that it was the powers that be, the political and religious elite. Thus, we are told, the death of Jesus shows the bankruptcy of these systems and calls us to oppose them. Now, on one level there is some truth in this. The Jerusalem elites wanted Jesus dead because he threatened their power. To Caiaphas the choice was between the life of one man and the survival of the nation. The fear was that a real live Messiah would destabilize everything and lead to a war with the Romans, a war the Jews could only lose - as it turned out in AD 70. Caiaphas was a politician, and he decided that if one act of injustice was to be the price for national survival, so be it.
Pilate was finally prevailed upon to agree to the crucifixion because the Jerusalem elite convinced him that to do otherwise would be to set himself against Caesar, against the Empire. Imperial peace and stability were what finally led Pilate to agree to what he knew to be an act of injustice. In the case of Pilate and of Caiaphas, while one can argue that they were motivated by self-interest, there is also a plea of 'the greater good'. There is the calculation that it is, in the final analysis, right to sacrifice one man for the lives of thousands.
But what is often overlooked is the common people. Their complaint was that Jesus was not the Messiah they wanted. Faced with the choice of setting free Jesus the Prince of Peace and Barabbas the violent revolutionary, they chose Barabbas. And they chose him freely, because he was the sort of leader they wanted, the leader Jesus was not, the man who promised liberation and victory over the Romans.
Jesus will not serve the Imperial agenda, but nor will he serve the revolutionary. He calls us to turn the other cheek, to go the extra mile, and to suffer for him. To die for him, not to kill for him. Now the cross is far more than this, but on the side of unbelieving men it is man killing God, because God will not fit in with our plans.