Just as little can we afford to follow the doctrinaires of an impossible - and incidentally of a highly undesirable - social revolution which, in destroying individual rights - including property rights - and the family, would destroy the two chief agents in the advance of mankind, and the two chief reasons why either the advance or the preservation of mankind is worthwhile.
It is hard to tell if capital punishment has such an effect. And even if, in some contexts it has (such as in the American South with a very high incidence of murder), this effect may very well go away if a decent welfare state was replaced for the existing social order.