Wisconsin hosted Nebraska in Madison on Oct. 29. In the stands at Camp Randall Stadium, one fan dressed in a Donald Trump mask, and that fan’s companion dressed in two masks: one for Hillary Clinton, one for President Obama.

The fan in the Trump mask depicted himself lynching his partner in the Obama and Clinton masks.

Here’s an angle from the back:

At the @UWBadgers game and there is a man with a mask of President Obama and a noose. This is racism, why was this allowed into the stadium? pic.twitter.com/zKEqhdDYny — (@woahohkatie) October 29, 2016

And a video that shows the costumes more fully, as the costume-wearers were leaving their seats. (Wisconsin said they were allowed to stay during the game, but the school thought the noose element of the costume had been removed.)

It APPEARS the men were first asked to removed the Obama mask then asked to leave. This was their exit... pic.twitter.com/Xv1UxMOfaW — (@woahohkatie) October 30, 2016

The person in the Clinton and Obama masks carried a sign that says “WHAT DIFFERENCE AT THIS POINT DOES IT MAKE?” It’s hard to make out the entirety of the sign from the obstructed view in the image above.

But what is easy to discern about this act is that it is racist. It depicts America’s first black president being lynched, along with Donald Trump’s presidential campaign opponent. It is jarring and upsetting.

Some of the people who saw the costume were angry that Wisconsin let it be worn into the stadium. University police tweeted that stadium staff asked the people involved to get rid of the noose, which they did. Other than that, university police said they were treating it as free speech.

The university says it regrets its initial response.

Wisconsin chancellor Rebecca Blank said on Monday a “noose displayed in this fashion has no place in Camp Randall,” and that Wisconsin would review the carry-in policies that apparently let the costumes through the gates initially.

I am personally very sorry for the hurt that this incident and our response to it has caused. I have heard from students, faculty and community members who are dissatisfied with our response, and I understand why. A noose is a symbol of some of the worst forms of racial hatred and intimidation in our country’s history. We understand this and we should have communicated this more forcefully from the beginning.

The athletic department has also commented since that Saturday.

Wisconsin AD Barry Alvarez on fan wearing Obama costume w/noose last Saturday: “I'm determined nothing like this will happen again" — Brett McMurphy (@McMurphyESPN) November 2, 2016

For reference, here’s part of the school’s initial statement, from the night of the game.

UW Athletics’ policy regarding admission into the stadium with a costume stipulates that no one may be wearing a mask upon entering the facility. Once inside, it is permissible to wear a mask. The costume, while repugnant AND COUNTER TO THE VALUES OF THE UNIVERSITY AND ATHLETIC DEPARTMENT, was an exercise of the individual’s right to free speech. The university also exercised its rights by asking the individual to remove the offensive parts of the costume. UW-Madison is dedicated to promoting a campus environment where all people feel valued, safe and able to thrive. To that end, the university continues to encourage all of our community members to engage in discussion over vital issues in ways that promote greater understanding and respect for all persons.

And here’s how the First Amendment applies to political protests in stadiums, in general.