He tells us that Jewish law, unlike secular law, does not sentence people to prison as a punishment (p. 11). Historically this has been true, but that is because the Jewish communities didn’t have real prisons. At most they had small jails to keep people for limited periods of time. (See R. Ephraim ha-Cohen, Sha’ar Ephraim, no. 83, who discusses if the communal jail needs a mezuzah.) If they were dealing with a real criminal who had to be stopped, they turned him over to the non-Jewish authorities or they dealt with him through physical punishments. Jewish courts in Spain would deal very harshly with those they wanted to punish. They even cut off tongues and noses as forms of punishment. Considering the alternative, one would think that Agasi would be happy that we have progressed to prisons, which seem much more humane than how medieval Jews dealt with troublemakers. Yet from Agasi’s standpoint, long prison sentences are what he regards as cruel and unusual punishment.
Marc B. Shapiro, “The Vilna Gaon, part 3 (Review of Eliyahu Stern, The Genius)”, The Seforim Blog (23 February 2014) [http://seforim.blogspot.com/2014/02/the-vilna-gaon-part-3-review-of-eliyahu.html]