Discuss.
I recently read an article by a religious historian. The guy stressed out some interesting points(I'm not qualified to comment on their validity).
First, Judas was not a poor man, and he did not come from the same background as the other Apostles. He apparently came from a rich family that usually ended up with top jobs in Judea. Hence the idea that he denounced Christ to the Romans because of 30 silver coins seems rather strange.
His family had been involved in uprisings against the Romans (IIRC), largely because they believed Judea would be ruled and saved by a Master of Justice, who would throw the occupiers out of Judea, along with merchants (who were often foreigners).
The theory of this historian is that Judas thought Jesus was this Master of Justice, and that he was growing bitter that Jesus did not reveal himself as such. Judas was also confused by some positions adopted by Christ, like when he saw that waht belonged to Caesar (the tax money) was to be given to Caesar, and when he said his realm was not of this world.
So, says this historian, it is to attain to the temporal power he was expecting from the Master of Justice that Judas denounced Jesus to give him no other choice but to preach open revolt and "holy" war against the Romans.
I will not comment on religious significance or validity of this article, but it made for a good story - and maybe some good History too.
As for his being selected by Jesus, well, since Christ was ready to make this ultimate sacrifice, giving his life to redeem Humanity, why couldn't He have chosen Judas fully knowing that it would be His downfall as a mortal being, and His revelation as God's Son ?