According to John 12 it actually started before the Last Supper. Judas did not like the way things were going at the beginning of Passover week A.D. 30, and objected to the extravagance of Mary's anointing Jesus feet with the ancient equivalent of a pint of Chanel No. 5. Judas protested the wasting of a whole year's salary which could have been used to help the poor. Jesus' response was curt--- "leave her alone, allow her to observe it" presumably referring to her observing a burial ritual in advance of Jesus' death, though Mary would not have realized the act had this significance. We are told that Judas was the one who carried the money bag for the Twelve, and there is the further editorial comment by the Evangelist that he was not really concerned for the poor, and that he had a habit of dipping into the till.
He was not the last disciple to let greed get the best of him. But even on this occasion it began to become clear that despite riding into town on a donkey to great Hosannas and despite the prophetic action in the Temple, Jesus had come to town to die, not to kill or to kick the Romans out of town. If Judas was like Simon the Zealot, this could only have been profoundly disallusioning.
There is some reason to think that Judas may have been a Zealot. His name 'Iscariot' could actually mean either man of Kerioth, or Sicarri--- which means dagger men. The Zealots had their hit men, called Sicarri and Judas may well have been one of them before he joined the Twelve. This is by no means certain but it is historically plausible. If this was Judas' background, then his dreams of what Jesus would accomplish at Passover A.D. 30 would have been shattered by the last supper in which Jesus made clear he was about to give his life for his disciples, and others. We must all beware when we love our vision and dream of the Kingdom more than we love Jesus-- for Jesus will require it of us. I suspect Judas was such a person.
And Jesus knew what Judas had in mind, even told him to go and do it quickly. This does not mean that Jesus put Judas up to it, unlike what the Gospel of Judas suggests. It does mean Jesus foresaw where this story was leading and he tried to prepare his disciples for the shocking end that was coming. So when Judas went out into the night on April 6th A.D. 30, it is not a surprise that they most symbolic of Gospels says at this point "and it was night". Indeed, it was midnight in the garden of evil, and Judas was willingly going to play a role in the handing over and betrayal of Jesus. There could hardly be a worse perfidy, and it is in no ways surprising that the portrait of Judas got darker and darker after NT times in post-apostolic literature. This is one of the things that makes the Gospel of Judas interesting-- it is bucking the tide on this point.
But what should we really think of Judas's act? For one thing we notice that altruism is ruled out. Judas did not merely betray Jesus on principle, he betrayed him for thirty Tyrian shekels, which comports with what John 12 tells us about his love of money. This was a doubly dubious act, not a noble one meant to aid Jesus on his way to becoming martyr, superstar, or to help him get into heaven a little quicker, sloughing off the flesh. Nothing in our earliest sources suggests anything noble about Judas' deed.
Leave Judas aside for one moment-- ask your self this question-- Would Jesus have forgiven Judas if he had repented and sought it? The Jesus who from the cross said to his tormentors and executions "Father forgive them for they know not what they do" could certainly have said this to Judas. But as my friend James Howell has said guilt and remorse over consequences is not the same as repentance.
We have evidence that there was remorse in the case of Judas-- he tries to give the money back, and according to one tradition he hangs himself, presumably ashamed of what he did. His actions suggest shame and guilt, but repentance is another thing. In an honor and shame culture there are plenty of occasions where one feels shame and guilt about how things turned out, but in fact is not prepared to repent of what one has done. We do not know if Judas did so. But equally we have no basis in the NT to say what later church fathers said--- namely that we know for sure he was damned for all time.
Jesus, it is true says "it would have been better if such a person had never been born" but this is a woe saying presumably meant to warn his disciples against such an action, not suggest that it was inevitable or predestined that Judas would do this. It must be remembered that John 13 says Satan entered Judas (compare Luke's account), not God. He became an emissary of the powers of darkness, not of the Heavenly Father, and so his deed must be seen as wicked, not as noble or even God-ordained.
But where does this leave us, with Judas hanging from a tree and Jesus hanging on a tree? What should we think of all this today? The universal offer of forgiveness by Jesus is a paramount part of his message. But forgiveness offered is not the same as forgiveness received. We must be content to leave the final judgment of Judas in God's hands, and not try to either blacken or exonerate his reputation on the basis of later Christian and not so Christian traditions.
When we think of Judas there should be one thought upper most in our mind when we look at how he ruined his life. We should reflect and say in our heart of hearts "there but for the grace of God go I." We must all repent and believe the good news of salvation in Jesus Christ. Only so will Good Friday and Easter be good news for us.