A majority of Indiana Republican legislators whose opponents were backed by Donald Trump lost their primaries on Tuesday, giving the president wins in a deep-red state just months after lawmakers there rejected his redistricting plan.

Of the seven Trump-endorsed challengers to state senate candidates, at least four won.

The vote turned into a statewide referendum on political retribution, and a test of Republican staying power after the party’s state lawmakers resisted Donald Trump’s bruising campaign to pressure them into redrawing the congressional districts.

Seven state senators who voted against Trump’s mid-decade redistricting push faced challengers endorsed by the president, who said that “every one of these people should be ‘primaried’” after the effort failed.

Trump-aligned dark money groups spent upwards of $7m on TV ads in Indiana this year, according to a tally from AdImpact – the majority spent targeting Republicans who allied themselves with Democrats in the December redistricting vote.

Jim Buck, a state senator from Kokomo, lost to a Trump-backed challenger after 18 years in office.

“We’ve never had Washington meddle into our elections like they have this time,” Buck told NPR. “Now I’ve got over $1m against me in one race.”

One ad disparaged the 80-year-old public servant by calling him “old, pathetic, liberal”.

Republicans control seven of Indiana’s nine congressional districts, and the overall balance of power is unlikely to change in this years’ midterm vote. Trump’s redistricting scheme took aim at breaking up Indiana’s first and seventh congressional districts, representing the urban centers of Indianapolis and Gary, where Democrats have consistently held seats.

Party-spending patterns indicate that they expect to hold the seats – Democratic advertisers make up less than 1% of the $25.5m in ad spending in the Indiana’s 2026 primary contest, AdImpact data shows.

Half of Indiana’s 50 state Senate seats and all 100 state House seats are up for election in 2026.

Unlike in Indiana, lawmakers in Texas, Missouri, North Carolina and Ohio all dutifully passed redistricting measures designed to boost Republican control. Representatives in Alabama and Tennessee have already called for special sessions to discuss redistricting after last week’s landmark supreme court ruling paved the way for revisions in Louisiana.

Democrats recently redrew the voting maps in California.

In the final days before Indiana’s contentious primary vote, Trump issued a call to his Truth Social followers, and instructed them to vote for a “true Maga Warrior”. If they needed help finding the polls, he included a link to voting locations on his party’s campaign engine, “Swamp the Vote”.

Associated Press contributed