Turnout for Wisconsin's Aug. 9 primary is predicted to be just 16 percent.
The Elections Commission estimate would be higher than the 14.5 turnout in 2014, but nowhere near the record-high of nearly 28 percent set in 1964.
There are several hot local primary races on the Aug. 9 ballot, but no compelling statewide contest to drive turnout.
House Speaker Paul Ryan faces a long-shot challenge from fellow Republican Paul Nehlen in his southeast Wisconsin congressional district.
There also is a three-way Republican race for the open 8th Congressional District in northeast Wisconsin.
There are also several contested primaries for seats in the state Legislature.
The Elections Commission turnout prediction released Thursday equates to nearly 712,000 voters.