Each election commissioner shall appoint other deputies, precinct and district inspectors, judges of election, clerks of election, deputy registrars, and peace officers to serve at elections and other assistants necessary for the performance of the duties of his or her office, the registration of voters, and the conduct of elections. Such employees shall be registered voters representing all political parties as nearly as practicable in proportion to the number of votes cast in such county at the immediately preceding general election for the office of Governor or President of the United States by the parties, respectively.