Insulation of a half guarantees majority rule tracks ex ante utilitarian welfare

Evidence

Choosing M = 1/2 will then guarantee that the alternative that maximizes total ex ante utility is always chosen, namely x whenever k > 1/2, and y otherwise. This reasoning extends to collective decision problems like ours that boils down to a utilitarian maximization problem: if M > 1/2 (resp. M < 1/2) then reforms would take place too (resp. not sufficiently) often from the standpoint where voters expect their preferences for reform to lie ex post. — Philippe Aghion, Alberto Alesina, and Francesco Trebbi, Endogenous Political Institutions, 72

Categorization

• DEEPTHINKING: M=1/2 as the knife-edge that makes majoritarian decision-making coincide with ex ante utilitarian welfare; deviations bias the frequency of reform.