There have been people down through the years who have argued the case in defence of Judas Iscariot. For me, the example of Judas' betrayal is a reminder that nobody can assume on God's love or take for granted their place in His family. Throughout history, there can have been no greater privilege than to spend three years in the company of Jesus Christ, the Son of God. As Jesus points out here, Judas has shared mealtimes with Jesus every day and that, especially in the Middle East is a sign of friendship and loyalty. David had also experienced that level of disloyalty and wrote about it in Psalm 41 v 9 and Psalm 55 v 12-14.
It is also a reminder that the redeeming of this world would cost the broken heart of God. However, it is all in God's purposes: Jesus knew what was to come and who it was who would betray Him. Judas does not just demonstrate here that he is the betrayer- in other versions, this passage ends with: 'He went out at once-and it was night'. Everything was now in place, but Judas shows here that he is also a hypocrite of the worst sort. The Pharisees and Sadducees made it clear to Jesus that they were His enemies; Judas could sit in the company of His disciples and not be recognised by the others as being Jesus' betrayer! It appears that, as John was sitting on Jesus' right, Judas must have been sitting on His left. This in Jewish culture was the place of highest honour. Jesus did all that He could to appeal to Judas' better nature, but to no avail. He, as with all of us, had free will, and chose to betray Jesus. You may argue that Judas was just fulfilling God's plan, that he had no real choice. However, we can see repeatedly throughout the Bible that there is always opportunity to repent, to turn back from the dark path, and those who do so, receive the welcome, forgiveness and loving kindness of the Lord God.