The First Amendment right to free speech extends far beyond just verbal expression. Some of the most iconic First Amendment cases have concerned the right to make silent but powerful statements, such as wearing a black armband to protest a war, Tinker v. Des Moines (1969), or an impolite shirt to protest the draft, Cohen v. California (1971). As these cases have recognized, what we choose to wear often plays an important role in how we express ourselves.

But in Minnesota, such personal expression has been unjustifiably prohibited. The state completely bans the wearing of any “political badge, political button, or other political insignia” in or around the polling place on election day. When several Minnesota citizens attempted to vote wearing clothes expressing support for the Tea Party movement or buttons reading “Please I.D. Me,” they were told that such apparel violated the law. They sued to overturn the law, but their challenge has twice been rejected by the U.S. Court of Appeals for the Eighth Circuit.

Now those voters have appealed to the Supreme Court. On the eve of our nation’s independence day, Cato, joined by the Rutherford Institute, Reason Foundation, and Individual Rights Foundation, has filed an amicus brief supporting that petition.

We explain just how startlingly far Minnesota’s statute extends. Anything from the word “occupy” to the peace symbol to a donkey or elephant might be construed as a “political insignia,” thereby running afoul of the law. Further, the statute gives election judges the power to ban any materials “promoting a group with recognizable political views.” That means Minnesota voters can’t even feel safe wearing shirts supporting the ACLU, NAACP, or their local union.

No compelling government interest justifies such a sweeping ban. Only once has the Supreme Court upheld a law that regulated speech in the polling place. But in that case, Burson v. Freeman (1992), the law was limited to “the solicitation of votes and the display or distribution of campaign materials.” Because that law specifically targeted electioneering, the Court held that it was narrowly tailored to advance “a compelling interest in protecting voters from confusion and undue influence.”

By instead banning all political insignia, Minnesota has gone vastly beyond Burson. Concerns about the electoral process can’t justify a ban on speech that is unrelated to any issue or candidate on the ballot.

Finally, we explain in our brief that the law is so vague it gives unaccountable election judges far too much discretion in determining what is permissible. So long as Minnesota’s law remains on the books, voters are left unsure whether any given government agent might rule that their Gandhi or Lennon (or Lenin!) shirt is a political stance or just a fashion statement. As a result, even apolitical speech has undoubtedly been chilled by the law, making it unconstitutionally overbroad.

The Supreme Court should take up Minnesota Voters Alliance v. Mansky and strike down Minnesota’s ban on political expression.