Voters in Indiana, Ohio and Michigan go to the polls Tuesday in the first multistate primary day of 2026, with seven Indiana state senators who voted against President Trump's congressional redistricting push facing primary challengers he endorsed.

The Indiana races, normally an afterthought on a national primary night, have drawn $11.8 million in ad spending, according to the tracking firm AdImpact. Less than $500,000 was spent on Indiana state Senate ads across the entire 2024 cycle. The contests measure how far Trump can punish Republicans who defy him in his second term, 182 days before the midterms.

The retribution slate

Trump endorsed challengers in seven of the eight Republican Indiana state Senate races where an incumbent who opposed redistricting is seeking re-election, according to the Associated Press. The GOP-led Indiana Senate killed the map last year when more than half of its Republican members sided with Democrats. Texas, Missouri, North Carolina and Ohio later answered Trump's call to redraw their lines; Indiana did not.

The targeted senators all sit in districts Trump carried in 2024, mostly by 20 points or more. The most competitive is District 1, near Lake Michigan, where Trump won by about 7 points. The safest is District 19, on the Ohio border, where he won by roughly 39 points.

Hoosier Leadership for America, aligned with Republican Sen. Jim Banks, is the largest outside spender at nearly $5 million, NBC News reported. American Leadership PAC, run by an adviser to Donald Trump Jr. and Vice President JD Vance, has spent more than $3 million. The incumbents have generally outraised their challengers and drawn support from the Indiana Senate Republican Caucus, which has spent more on these races than it did on all of 2022.

Ohio's open seats

Ohio voters will set up two of the cycle's most-watched November contests. Vivek Ramaswamy, the biotech entrepreneur and 2024 presidential candidate endorsed by Trump in November, is positioned to win the GOP gubernatorial nomination after Attorney General Dave Yost dropped out in May 2025 and Lt. Gov. Jim Tressel declined to run. The Associated Press reported that the remaining challenger, auto-racing engineer Casey Putsch, had less than $9,000 in his account at the end of April compared with $31 million for Ramaswamy. Former state health director Amy Acton is unopposed in the Democratic primary.

In the special Senate primary to fill the final two years of Vance's seat, appointed Republican Sen. Jon Husted is unopposed. Former Democratic Sen. Sherrod Brown, who lost to Bernie Moreno in 2024 by less than four points in a state Trump won by more than 10, faces only Ron Kincaid. Democrats see Brown-Husted as one of a handful of contests that could decide control of a chamber where Republicans hold a 53-47 majority.

Michigan tiebreaker

Voters in Michigan's Saginaw Bay area will fill a vacant state Senate seat formerly held by Democratic Rep. Kristen McDonald Rivet. Then-Vice President Kamala Harris carried the district by less than 1 percentage point in 2024, NBC News reported. Democrats nominated Marine veteran Chedrick Greene; Republicans nominated former prosecutor Jason Tunney. A Republican win would tie the chamber 19-19 and leave the Democratic lieutenant governor with the deciding vote.

The dissent

State Sen. Spencer Deery, one of the targeted Indiana incumbents, told NPR the White House campaign violates conservative federalism. "What is being set up here is the potential model for any party to raise ridiculous amounts of money in D.C. and then to use that to try to control the states," Deery said. Marty Obst, the Republican consultant who led the redistricting push, told NPR that "there's consequences and accountability" for blocking a presidential priority.

A pro-Trump source involved in the Indiana races told Fox News Digital that winning half the targeted seats would be considered a victory and anything beyond that a major win. Most polls in Indiana close at 6 p.m. Eastern; Ohio polls close at 7:30 p.m. Eastern.