A police union is a trade union for police officers. Police unions formed later than most other occupations, reflecting both a conservative tendency and relatively superior working conditions.[1] The first police unions formed in the United States. Shortly after World War I, the rising cost of living, wage reductions, concerns over amount of rest and growing dissatisfaction among rank and file police officers led to a number of police strikes from 1918–1923 and the formation of police unions globally.[1]