Public employee unions have long been active in the municipal politica
l process, but there have been few studies of the determinants of this
activity. Using the most recent version of a national survey of munic
ipal labor relations, a number of trends for police unions were discov
ered. The decrease in political activity observed in the late 1960s an
d through the 1970s appears to have ended. This study found particular
ly large increases in candidate endorsements and financial contributio
ns, with the only decline occurring in state-level lobbying. In terms
of the determinants of the political activity by police unions, a numb
er of factors proved significant. The most important included the perc
entage of homeowners in a city, the existence of a bargaining agreemen
t, and union size, all of which generally increased the level of polit
ical activity by a police union.