The Supreme Court, in the case of Minnesota Voters Alliance v. Mansky, ruled that a Minnesota law that banned “political badge, political button, or other political insignia” at polling places on Election Day was unconstitutional.

The case was brought by voters who, among other things, wanted to wear a Tea Party Patriots tee shirt (see featured image, via MVA Facebook):

Petitioner Minnesota Voters Alliance (MVA) is a nonprofit organization that “seeks better government through election reforms.” Pet. for Cert. 5. Petitioner Andrew Cilek is a registered voter in Hennepin County and the executive director of MVA; petitioner Susan Jeffers served in 2010 as a Ramsey County election judge. Five days before the November 2010 election, MVA, Jeffers, and other likeminded groups and individuals filed a lawsuit in Federal District Court challenging the political apparel ban on First Amendment grounds. The groups—calling themselves “Election Integrity Watch” (EIW)—planned to have supporters wear buttons to the polls printed with the words “Please I. D. Me,” a picture of an eye, and a telephone number and web address for EIW. (Minnesota law does not require individuals to show identification to vote.) One of the individual plaintiffs also planned to wear a“Tea Party Patriots” shirt….

One individual was asked to cover up his Tea Party shirt. Another refused to conceal his “Please I. D. Me” button, and an election judge recorded his name and address for possible referral. And petitioner Cilek—who was wearing the same button and a T-shirt with the words “Don’t Tread on Me” and the Tea Party Patriots logo—was twice turned away from the polls altogether, then finally permitted to vote after an election judge recorded his information.

The Supreme Court, in an opinion authored by Chief Justice Roberts (with Sotomayor and Breyer dissenting) did not rule that politics couldn’t be kept out of polling places. To the contrary, the court made clear that the state has a legitimate interest in keeping campaigning out of polling places:

… our decisions have long recognized that the government may impose some content based restrictions on speech in nonpublic forums, including restrictions that exclude political advocates and forms of political advocacy. See id., at 806–811; Greer v. Spock, 424 U. S. 828, 831–833, 838–839 (1976); Lehman v. Shaker Heights, 418 U. S. 298, 303–304 (1974) (plurality opinion); id., at 307–308 (Douglas, J., concurring in judgment).

A polling place in Minnesota qualifies as a nonpublic forum. It is, at least on Election Day, government controlled property set aside for the sole purpose of voting….

We therefore evaluate MVA’s First Amendment challenge under the nonpublic forum standard. The text of the apparel ban makes no distinction based on the speaker’s political persuasion, so MVA does not claim that the ban discriminates on the basis of viewpoint on its face. The question accordingly is whether Minnesota’s ban on political apparel is “reasonable in light of the purpose served by the forum”: voting.

* * *

… we see no basis for rejecting Minnesota’s determination that some forms of advocacy should be excluded from the polling place, to set it aside as “an island of calm in which voters can peacefully contemplate their choices.” Brief for Respondents 43. Casting a vote is a weighty civic act, akin to a jury’s return of a verdict, or a representative’s vote on a piece of legislation. It is a time for choosing, not campaigning. The State may reasonably decide that the interior of the polling place should reflect that distinction….

Thus, in light of the special purpose of the polling place itself, Minnesota may choose to prohibit certain apparel there because of the message it conveys, so that voters may focus on the important decisions immediately at hand.

The court went on to hold that the law was too vague and left too much discretion to those enforcing the law:

But the State must draw a reasonable line. Although there is no requirement of narrow tailoring in a nonpublic forum, the State must be able to articulate some sensible basis for distinguishing what may come in from what must stay out. See Cornelius, 473 U. S., at 808–809. Here, the unmoored use of the term “political” in the Minnesota law, combined with haphazard interpretations the State has provided in official guidance and representations to this Court, cause Minnesota’s restriction to fail even this forgiving test.

Again, the statute prohibits wearing a “political badge, political button, or other political insignia.” It does not define the term “political.” And the word can be expansive…. Under a literal reading of those definitions, a button or T-shirt merely imploring others to “Vote!” could qualify….

We do not doubt that the vast majority of election judges strive to enforce the statute in an evenhanded manner, nor that some degree of discretion in this setting is necessary. But that discretion must be guided by objective, workable standards. Without them, an election judge’s own politics may shape his views on what counts as “political.” And if voters experience or witness episodes of unfair or inconsistent enforcement of the ban, the State’s interest in maintaining a polling place free of distraction and disruption would be undermined by
the very measure intended to further it.

So today was a victory for free speech. Until further notice, you can wear your Tea Party shirt to vote in Minnesota, and the gubmint can’t tread on it.