WASHINGTON — Five of seven Republican Indiana state senators who successfully voted to block a Trump-backed redistricting plan last year lost their primaries Tuesday, after the president endorsed challengers against them.
The result underscored the influence of an endorsement by Trump, who has been active in races both on the state and federal level. Among decided primary races in 2026, Trump-backed candidates have won about 95% of the time, according to Ballotpedia.
Jesse Crosson, a political science professor at Purdue University, said “the Trump endorsement is worth far more than the money, because what happens in any partisan primary is that people don’t have the time, inclination, or information to learn about the candidates on their own merits.”
Crosson went on to say the night’s results should be understood in the context of the redistricting vote last December.
There were 21 Republicans who voted against redistricting when the bill came to the Senate floor. Seven of those 21 Republicans were challenged in the primaries by Trump-backed opponents.
“Even if all [seven] had lost, there would have been 14 Republicans who voted against the bill left. I suspect the reason they chose seven is because it was a 15 vote margin in the Senate to redistrict,” Crosson said.
Crosson said how the goal wasn’t to eliminate dissent entirely, just to shrink the opposition to just under the margin the redistricting failed by, ensuring that even a unified coalition of Democrats and those same Republicans couldn’t block a similar vote in the future.
One notable result of one of the Indiana State Senate races in which Trump endorsed a candidate occurred in Crosson’s district—and the district Purdue University is situated in. The initial vote is reported to be 6,334 to 6,331, with the incumbent, Sen. Spencer Deery, R-West Lafayette, ahead by a mere three votes. Deery voted against the redistricting bill in Indiana and is being challenged by Trump-backed Paula Copenhaver.
“Turnout definitely was up with almost 13,000 votes in that election,” said Crosson. “Three votes out of almost 13,000 is pretty remarkable.”
Sam Barloga, communications director for the Indiana Democratic Party, said that Democratic primary turnout was also high and argued that some independent voters who normally participate in Republican primaries instead chose Democratic ballots this year.
“The type of electorate that showed up on the Republican side was their most die-hard base voters,” Barloga said, suggesting that the shift could have contributed to the defeats of the incumbents that had opposed the redistricting plan.
Republicans currently hold supermajorities in both the Indiana House of Representatives and Senate, with 70 and 40 seats, respectively. Barloga said Indiana Democrats are largely focused on breaking the supermajorities in the general election later this year.
“What worries me is that the chamber and the legislature, more generally, is going to find a way to get even more radical,” Barloga said. “We’re down 70 to 30 on the State House side…even if we just pick up four seats, we break the super majority, which means a lot of things like extra seats on committees and [being able to] stop some conference committee bills, so I think that is really important.”
President Pro Tempore Rodric Bray, R-Martinsville, declined to comment. Bray was one of the 21 Senate Republicans that voted to block the Trump-backed redistricting plan.