Chief Justice Roberts, writing for the seven-justice majority, first concluded that because the polling place is a non-public forum, Minnesota could indeed "choose to prohibit certain apparel there because of the message it conveys, so that voters may focus on the important decisions immediately at hand."
But the Chief Justice described how broad Minnesota's ban is (citations omitted):
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. 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. It can encompass anything “of or relating to government, a government, or the conduct of governmental affairs,” or anything “[o]f, relating to, or dealing with the structure or affairs of government, politics, or the state.” Under a literal reading of those definitions, a button or T-shirt merely imploring others to “Vote!” could qualify.
As was made abundantly clear by the state's counsel during oral argument, Chief Justice Roberts then described how Minnesota could not even define or consistently describe what apparel would and would not be banned by the law, noting that the law "poses riddles that even the State’s top lawyers struggle to solve." (citations omitted):
“[P]erfect clarity and precise guidance have never been required even of regulations that restrict expressive activity.” But the State’s difficulties with its restriction go beyond close calls on borderline or fanciful cases. And that is a serious matter when the whole point of the exercise is to prohibit the expression of political views.
It is “self-evident” that an indeterminate prohibition carries with it “[t]he opportunity for abuse, especially where [it] has received a virtually open-ended interpretation.” Election judges “have the authority to decide what is political” when screening individuals at the entrance to the polls. 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.
The Chief Justice concludes by noting that other states have bans on apparel and insignia at the polling place that are much more clearly defined (citations omitted):
We do not suggest that such provisions set the outer limit of what a State may proscribe, and do not pass on the constitutionality of laws that are not before us. But we do hold that if a State wishes to set its polling places apart as areas free of partisan discord, it must employ a more discernible approach than the one Minnesota has offered here.
Cases like this “present us with a particularly difficult reconciliation: the accommodation of the right to engage in political discourse with the right to vote.” Minnesota, like other States, has sought to strike the balance in a way that affords the voter the opportunity to exercise his civic duty in a setting removed from the clamor and din of electioneering. While that choice is generally worthy of our respect, Minnesota has not supported its good intentions with a law capable of reasoned application.
As the opinion notes, not only did this law burden voters and leave them vulnerable to unequal enforcement, it also placed burdens on hardworking poll workers (who have many other tasks on Election Day) to both interpret and enforce an unclear law. This decision is a victory both for the First Amendment rights of voters but also for good election administration, as states do their local election officials and poll workers an immense disservice and cause disruptions when they provide unclear guidelines for procedures at the polling place.