Minnesota has a law banning voters at the polls from wearing any clothing, or anything on their person, with a political message. The ban doesn’t just cover messages relating to items that are on the ballot. Most states that have restrictions on clothing at the polls limit the restriction to clothes that relate to some candidate, party, or ballot measure that is actually on the ballot in that election; Minnesota’s ban is far broader.
The lower federal courts upheld the Minnesota law in Minnesota Voters Alliance v Mansky, and the plaintiffs then asked for U.S. Supreme Court review, case 16-1435. On June 15, Minnesota told the U.S. Supreme Court that it waives its right to file a brief in this case. If the U.S. Supreme Court is interested in hearing this case, it will undoubtedly ask the state to respond. But that won’t be until October 2017 at the earliest, because the Court is about to go on its summer recess.
The particular clothing items in this case were T-shirts mentioning the Tea Party. The Tea Party has never been on the ballot in Minnesota, where it has only functioned as a pressure group.