Jesus was about as popular to the political/religious authorities in Israel those days as Edward Snowden is in the USA today. It was only a matter of time before Jesus was turned in by one of his followers.
Whether it was Judus' freewill to do this, I don't doubt a bit. He made the choice to do the things that the authorities requested, he was actually being the model citizen doing what he was asked to do.
Would you turn in Edward Snowden in? Are you the modern day Judas?
http://en.wikipedia.org/wiki/Edward_Snowden