The presidential primary season may be over with President Joe Biden and former President Donald Trump heading for a rematch, but several down-ballot races are up for grabs that will determine control of Congress. Ohio’s primary on Tuesday will decide which Republican takes on Democratic incumbent Sen. Sherrod Brown in November, as well as congressional contests key to the GOP House majority. This series, Buckeye Blitz, will examine the politics behind the races and the issues that will drive 2024 turnout. Part Two, below, looks at how the Ohio Senate primary has become the latest test of the former president’s sway with Republican voters.

COLUMBUS — The weight of Donald Trump’s endorsement is unquestioned in Republican politics. It can send a candidate to the front of the pack in a crowded primary, as it did for Sen. J.D. Vance (R-OH) in 2022’s Ohio Senate race.