Tucson, Arizona, has partisan elections for city council. The unusual Tucson law provides that parties nominate in primaries within each district. But, in the general election, all the seats are contested citywide. The Ninth Circuit had originally ruled that this system violates the Constitution, but then the City of Tucson had asked for rehearing en banc, and the en banc panel upheld the system.

The voters who brought the lawsuit then asked the U.S. Supreme Court to take the case, but on March 20, the Court declined. The case was Public Integrity Alliance v City of Tucson, 16-730. Thanks to Michael Drucker for this news.