On the perils of commitment to punishment when criminals are strategic

For some crimes the perpetrator can be detected costlessly but can be apprehended only at significant cost or not at all for some period of time. To deter strategic behavior in the period between detection and apprehension, authorities may wish to commit themselves to punishing the perpetrator once apprehended, regardless of his behavior or threats. However, we show that such efforts at commitment to ex post punishment may induce worse behavior and that it selects potential criminals of a worse type. We show that when law enforcement authorities cannot commit themselves perfectly, it is dangerous for them to try to commit, as it may invoke a strategic response that can worsen the situation. When law enforcement authorities do increase their commitment to punish such offenders, it is likely to lead to fewer but more gruesome crimes.