A Little About Missouri's Sheriffs
According to Wikipedia, "The political election of a person to serve as a police leader is an almost uniquely American tradition."
Currently, in the state of Missouri, a sheriff is elected to a four-year term of office. They are the senior law enforcement official within the county. Missouri's sheriffs are required to obtain a Missouri Peace Officer's Licence in order to serve in the elected position and must provide a bond to the State of Missouri in the amount of $5,000 within 15 days of being elected. There are other conditions concerning the office that may be read online.
Missouri passed legislation in 1813 establishing the office of sheriff. Initially sheriffs were elected every two years. In the 1908 election, this changed, and sheriff's were elected for four-year terms.