WESTERVILLE, Ohio

President Donald Trump’s preferred congressional candidate — and his chief legislative achievement — are about to be tested in battleground Ohio in the season’s final high-stakes special election.

The midsummer affair comes as Trump’s shadow looms over primary contests in four other states today, none bigger than Kansas, where the Republican president roiled the governor’s race Monday by opposing the sitting GOP governor on the eve of the election.

The races, like dozens before them, pit the strength of the Republican president’s fiery coalition against the Democratic Party’s anti- Trump resistance. The results will help determine the political landscape — and Trump’s standing within his own party — just three months before the GOP defends its House and Senate majorities across the nation.

Voters in Ohio and Kansas join those across Missouri, Michigan and Washington state at the ballot box. But only Ohio will send someone to Congress after the votes are counted.

The script for Ohio’s special election is perhaps familiar:

An experienced Trump loyalist, two-term state Sen. Troy Balderson, is fighting off a strong challenge from a fresh-faced Democrat, 31- year-old county official Danny O’Connor, in a congressional district held by the Republican Party for more than three decades.