The case is Minnesota Voters Alliance v. Mansky, Here’s the question presented from the cert. petition:

Minnesota election law forbids voters from wearing political badges, political buttons, or other political insignia at the polling place. See Minn. Stat. § 211B.11. The ban broadly prohibits any material “designed to influence and impact voting,” or “promoting a group with recognizable political views,” even when the apparel makes no reference to any issue or candidate on the ballot. The Eighth Circuit, aligned with the Fifth and D.C. Circuits, invoked Burson v. Freeman, 504 U.S. 191 (1992), to hold that a state can impose a “speechfree zone” without infringing on the Free Speech Clause of the First Amendment. There is deep tension between those decisions and the reasoning in decisions of the Fourth and Seventh Circuits, which hold that the First Amendment does not allow a state to prohibit all political speech.

The question presented is: Is Minnesota Statute Section 211B.11, which broadly bans all political apparel at the polling place, facially overbroad under the First Amendment?

This is the kind of knotty First Amendment question that the Court has shown an interest in taking in recent years, and the result of the case could be relevant not only to speech at polling places, but also to the line between election advocacy and issue advocacy which affects the scope of campaign finance laws.