Seven Republican state senators lost primary elections in Indiana on May 5, including six who voted against mid-decade redistricting. Two races remained uncalled as of May 6.

One Republican state senator who voted against redistricting has won their primary so far — Greg Goode, who defeated two challengers including President Donald Trump-endorsed Brenda Wilson.

This was the first year since Ballotpedia began tracking this data in 2010 in which more than one incumbent Republican senator was defeated in Indiana primaries.

There were 16 contested Republican incumbents in the state Senate in 2026. The average number of contested Republican incumbents in the Indiana Senate each year since 2010 was three. There were a total of 29 Republican incumbents in primaries in 2026 across the state House and Senate, a record high since 2010.

Before Indiana's mid-decade redistricting effort failed in the state Senate in December 2025, President Donald Trump (R) wrote in a Truth Social post: "Anybody that votes against Redistricting, and the SUCCESS of the Republican Party in D.C., will be, I am sure, met with a MAGA Primary in the Spring." Twenty-one Republicans joined the chamber's 10 Democrats in voting against redistricting.

Ten of the 21 Republicans who voted against the effort were up for re-election this year. Two of those 10 Republicans — Eric Bassler and Kyle Walker — did not run for re-election.

Trump endorsed several primary challengers running against Republican senators who voted against redistricting:

According to the Indiana Capital Chronicle's Tom Davies, a group affiliated with U.S. Sen. Jim Banks (R) released radio and digital advertisements against the Republican senators who opposed redistricting in March 2026: "The ads that started appearing last week follow the theme that the senators opposed 'President Trump’s plan to remove liberal Democrats from Congress' along with knocking them for votes on gasoline or property taxes and foreign land ownership."

Politico’s Samuel Benson and Adam Wren wrote that a spokesperson for Turning Point Action said that the organization would oppose the incumbents who voted against redistricting and that “the group would partner with other aligned PACs to dedicate an ‘eight-figure spend’ to ‘primary people that are standing in the way of the president’s agenda.’” Wren also reported that Banks’ Hoosier Leadership For America planned to spend $3 million on state Senate races.

WFYI's Caroline Beck wrote, "Former Indiana Republican Gov. Mitch Daniels is lending his political will and name power to help campaign for current Republican state lawmakers being primaried by Trump-supported candidates." Daniels said, "I think it's important that people who are fine public servants and have shown it in other contexts, who stood up for a principle here and showed bravery in so doing, that ought to be rewarded, not punished, and it's certainly not going to be punished by people from several hundred miles away who couldn't find Indiana with a road map."

Heading into the elections, Republicans had a 40-10 majority in the Senate. The state has had a Republican trifecta since 2011.