How does Jem propose to fix the problem of juries convicting innocent black men? How does Atticus propose to fix the problem?

From the text:

“Then it all goes back to the jury, then. We oughta do away with juries.” Jem was adamant.

Atticus tried hard not to smile but couldn’t help it. “You’re rather hard on us, son. I think maybe there might be a better way. Change the law. Change it so that only judges have the power of fixing the penalty in capital cases.”