A Republican who ran for Arizona governor in 2014 and a former Democratic lawmaker are jumping into the 2018 race for the seat held by Superintendent of Public Instruction Diane Douglas.

Former U.S. Rep. Frank Riggs announced his bid for the seat now held by a fellow Republican on Tuesday. He joins Peoria resident Tracy Livingston in challenging Douglas in next year's GOP primary.

Former Democratic state lawmaker and current Tempe city councilman David Schapira also announced his intention to seek the top Arizona schools office on Tuesday. Glendale resident Kathy Hoffman has already announced her plan to run for the Democratic nomination.

Douglas was a political newcomer when she upset incumbent John Huppenthal in the 2014 GOP primary, then went on to win the general election.