On February 27, the Indiana Supreme Court upheld the law that requires primary candidates to have voted in each of the last two primaries, and to have chosen the primary ballot of the party in which the candidate seeks to run. State ex rel John Rust v Morales. The decision is not yet on the Indiana Supreme Court’s website. See this story.
The lower state court had struck down the law. The law also says that if a political party wishes to waive the rule for any particular candidate, it may do so. But the Republican Party did not grant a waiver for John Rust, so he can’t be on the May 2024 Republican primary for U.S. Senate. The decision leaves just one candidate on that ballot.