I mean the "obvious" alternative that satisfies those predicates is house arrest: separated from society, not in danger from other prisoners. So I'd ask: What

I mean the "obvious" alternative that satisfies those predicates is house arrest: separated from society, not in danger from other prisoners. So I'd ask: What prevents us from using house arrest as an alternative to imprisonment more often? How can those problems be addressed? Can we "build a better house arrest" -- maybe even from within the private sector?