Pilate was being pressured by the Jewish leaders to crucify Jesus and Pilate was not wanting to be pushed around by people that he was not fond of.  But, much like modern times, Pilate was under political stress of rioting by the Jews.  Pilate wanted to keep the peace.  Though Pilate found no fault in Jesus and thought the accusations were brought on by jealousy, the pressure to make judgment or wash his hands ended to be an affirmation to crucify.  Jesus was led as a lamb to slaughter and submitted as our sacrifice.  Ironically someday the righteous Judge, our Lord Jesus will condemn those who condemned Him.