Based on recent history, about 20 percent of Mercer County’s registered Democrats and Republicans could be expected to cast votes Tuesday in the primary.

But circumstances could change that expectation.

A high-profile race of potentially historic proportions at the top of the ticket and several contentious local races could increase voter participation for the 2019 municipal primary.

In the previous three municipal primary elections where the three county commissioners were on the ballot, turnout has been declining steadily, from 25.59 percent in 2007 to 23.68 percent in 2011 and finally to 19.84 in 2015. But this year’s primary is filled with potentially interesting races.

On Tuesday, Mercer County voters will select two Common Pleas Court judges in each party, in what will be the first time in at least 15 years that the county’s highest court has had two vacancies.

The county has had to fill single judicial vacancies in 2013 and 2011. But online records from the county Department of Voter Registration and Election, which go back to 2005, show no election with two open judge seats.

Candidates for the two seats are Ronald Amrhein of South Pymatuning Township, Michael Joanow of Hermitage, Margaret Lucas of Hermitage, Ryan Mergl of Sharon and state Rep. Tedd Nesbit of Grove City.

All five of the candidates are crossfiled for both Democratic and Republican nominations. Common Pleas Court of Mercer County has been operating with two judicial vacancies since the beginning of 2018, after judges Thomas Dobson and Christopher St. John retired.

After two years, those vacancies will be filled in January, most likely by two of the above five candidates.

County Republican voters will settle GOP nomination races for county commissioner, district attorney and sheriff.

Newcomer Marcus Kohan is running against incumbents Scott Boyd and Matt McConnell for two Republican county commissioner nominations.The third county commissioner, Democrat Tim McGonigle, and Dr. Robert Multari are effectively running unopposed for their party’s two nominations.

Pete Acker, who was appointed district attorney after Miles Karson was convicted of multiple felonies, is seeking election to the office against Sharon attorney Dustin Cole.

Sheriff’s deputies Bruce Rosa and Anthony Tedesco are seeking the Republican nomination to run the department.

The 2019 primary is potentially historic also because this will likely be the last time Mercer County voters will use the iVotronic touch-screen voting system. On Thursday, the county commissioners approved a contract with ES&S of Omaha, Neb., to supply a system that will incorporate a scanner that counts paper ballots and a ballot marking device.

Jeff Greenburg, Mercer County director of voter registration and election, said he expects to have the new voting system in place for the 2019 municipal general election in November.

In Grove City, seven candidates are seeking five Democratic nominations and nine Republicans are running for five nominations in their party. Because school board races are non-partisan, the seven candidates running for the Democratic nods also are on the GOP ticket.

Seven candidates are seeking Republican nominations in Lakeview School District and 10 candidates are running for nominations in Sharpsville area.

The polls will be open Tuesday from 7 to 8 p.m.