Law Professor Stephen Rushin’s 2017 study of police union contracts provides one possible answer. Rushin notes that these employment agreements are usually negotiated in secret, and that
municipal leaders may be strongly incentivized to offer concessions to police unions on disciplinary procedures in exchange for lower officer salaries. Because municipal expenditures can dominate local headlines, the result is a sort of moral hazard. Municipal leaders may be incentivized to offer concessions on police disciplinary procedures because they are less likely to bear the costs of those concessions in the immediate future. After all, the typical victim of police misconduct is often a member of a relatively small and politically disadvantaged minority of municipal voters.Stephen Rushin, Police Union Contracts, 66 Duke L. J. 1191, 1216 (2017).