The gospels present us with the range of political options that Jesus encountered in his life and ministry.
Collaboration was the only option for those who wished to achieve wealth and a degree of power in the world of the Roman empire. Rome mastered the art of engaging collaborators through the cooperation of local elites. Herod and the Saducees made this their political choice. surrendering effective control to Rome while maintaining a semblance of formal religio-political independence - a semblance that the gospel writers deconstruct.
The strategy of Reform relied on a theological reading of the history of Israel that called for a return to holiness and the call of the covenant. The call to purity was not an option for those who were poor. The Pharisees sought to interpret the call to purity for the masses in a way that built popular support from the masses without handing over religious and political power to them or politically confronting the powers of empire.
Withdrawal was the option of the Essenes that focused on withdrawing from confronting the reality of Roman occupation while practising some of the virtues, care for the sick and hospitality to strangers but no real vision for demonstrating the public character of God's kingdom.
Restorationism, the Zealot option, was the attempt to return to the golden age of Israel's empire and kingdom. They were about a change of government not the inauguration of a radically different social and political order.
The comparison between Jesus and the Zealots establishes two things. One is that Jesus had established a new for of life that others saw as a political threat. the other is that Jesus had no intention of translating that social program into a violent revolution. (p. 66)While Barabbas is not formally identified as a Zealot, his identification with the option of violence places him in direct contrast with Jesus. the Gospel writers are all clear that the crowds all clearly choose his option rather than that of Jesus and the powers that be are happy for this choice to be made. Jesus represents a more fundamental challenge to their rule than does Barabbas.
Barabbas represents a challenge that changes too little. Jesus comes to bring radical change rather than continue business as usual. Jesus challenges the endless cycle of violence. Barabbas simply wants to change the identity of who is in control of the political/social/religious power structure.