On September 2, Jason Gonzales, an Illinois candidate for the legislature in 2016, asked the U.S. Supreme Court to hear his case. Gonzales v Madigan, 21-352. Here is the cert petition. The case began when incumbent Illinois representative Michael Madigan recruited two candidates to run in the Democratic primary. Both candidates had Hispanic surnames. Madigan was already facing Jason Gonzales and the district was majority-Hispanic. Gonzales sued, presenting evidence that the two candidates recruited by Madigan were not bona fide candidates, but were merely brought into the primary to split the Hispanic vote. The Seventh Circuit in 1974 had ruled that bringing sham candidates into an election can violate the U.S. Constitution.
Gonazles lost in the U.S. District Court and the Seventh Circuit, despite the 1974 precedent. Illinois is in the Seventh Circuit.