With public pressure going on, Pilate was afraid (19:8). Pilate demonstrates how fear (especially fear of public approval) can be a major factor in succumbing to public pressure. From the fear, Pilate asked Jesus a few questions.
First, Pilate asked Jesus where He is from. Jesus did not say anything in response to the question. Albert Barnes noted that Jesus did not answer likely because Jesus already told Pilate about the "not of the world" kingdom -- not to mention Pilate himself believing Jesus to be innocent (Study Light). It's also likely that the question of origin is irrelevant at this time (especially with Pilate knowing Jesus's innocence).
Additionally, regarding Jesus not responding, Pilate rhetorically asked regarding the power to crucify Jesus. But Jesus did give a response -- Jesus said that "[Pilate] could have no power [...] unless it had been given [to Pilate] from above" and that "the one who delivered [Jesus] to [Pilate] has the greater sin" (19:11). Jesus technically has the power to escape from the crucifixion with the powers. In previous attempts to capture Jesus, He has escaped. Jesus even demonstrated his authority. However, Jesus ALLOWED others to crucify him because it was part of the plan of Jesus (and the Father).