Proportionality’s Constraint

Abstract This chapter addresses what it means for punishment to be proportional. It starts with an account of why proportionality matters, and why it is hard to account for it, given the multiple dimensions of input and output. Section 8.2 discusses the idea of “negative proportionality”—i.e., that punishment must not be clearly disproportionate—and explains it in terms of ordinal and anchored cardinal proportionality. Section 8.3 defends the thought that we can, in a range of applications, move tolerably well between multiple dimensions of input into a single value, and from a single value into multiple dimensions of output. Section 8.4 discusses the concrete implications of proportionality for sentencing defendants to death or to long terms in prison. Finally, Section 8.5 raises, and responds to, the objection that the notion of proportionality developed here is too conventional and that it runs into problems when thinking about universal jurisdiction.