NASHVILLE, Tenn. (AP) — After a raucous first debate led organizers to introduce a mute button, the second and final meeting between President Donald Trump and Democratic challenger Joe Biden was a downright civil affair.

Whether because of that button this time or the terrible reviews in the first debate — especially for Trump — the candidates interrupted each other far less frequently Thursday night, even as they clashed on issues including the coronavirus, crime and global warming.

While Trump and Biden responded to the other's answers — shaking their heads disapprovingly or smiling, in the case of Biden — the two largely avoided speaking over each other.

Trump, in particular, was on his best behavior, especially early on, and especially when it came to the moderator, whom he'd repeatedly denigrated before the debate.

“So far, I respect very much the way you’re handling this," Trump said to NBC's Kristen Welker when she gave him time to respond to Biden at one point.

The scene inside the sparsely populated college arena was representative of the performance on stage. The audience followed the rules exactly as laid out — they were remarkably silent throughout the 90-minute debate, and everyone appeared to be wearing masks.

Because of the pandemic, only around 200 people were seated inside the debate hall at Belmont University in Nashville. That included a representative of the Commission on Presidential Debates, who was tasked with ensuring each candidate had a two full minutes of uninterrupted time to deliver opening answers on six major topics, according to debate commission chair Frank Fahrenkopf.

A member of each of the Trump and Biden campaigns monitored the person who controlled the mute button backstage, Fahrenkopf told The Associated Press, noting that the button would not be used beyond the first four minutes of each topic.

The button was among a handful of changes implemented by the nonpartisan debate commission to help ensure a more orderly debate following the raucous and widely criticized opening debate 23 days ago. Coronavirus restrictions also remained in place, with attendees required to wear masks at all times and audience members distanced.

Organizers had initially planned to separate the candidates with plexiglass barriers, but the barrier were removed hours before the debate began. A Trump campaign official said the decision was made after White House chief of staff Mark Meadows called Dr. Anthony Fauci, the nation’s highly respected top infectious-diseases expert, during a walkthrough of the venue site.

Meadows put Fauci on speakerphone, and Fauci told those in the room that all a barrier would do was provide a false sense of security, the official said.

Trump was diagnosed with COVID-19 two days after the last debate, and he and the White House have refused to say whether he abided by commission rules and tested negative for the virus before that debate.

This time, Trump was given a test aboard Air Force One en route to Nashville on Thursday and tested negative, according to Meadows. Biden's campaign reported he also tested negative.

The debate commission also tightened its rules on masks, with organizers saying that any audience member who refused to wear one would be removed. Last month, several members of the Trump family removed their masks once seated in the debate hall, but were allowed to stay. This time, first lady Melania Trump, appearing in public for the first time since her own coronavirus diagnosis, as well as other members of the Trump family wore masks throughout.

Before the debate began, Fahrenkopf repeated the instruction to the small audience.

“If you won’t leave, you’ll be escorted," he said.

Fahrenkopf had said in an earlier interview that the safety measures would help reduce the risk of infection.

“The Trump campaign's attitude was that the president was not contagious anymore, but we’re going to go with our medical advisers," he said.

As a result, the president of Belmont University called it “the safest place in America tonight."

The university, a picturesque institution of more than 8,200 students just a mile from Nashville’s Music Row, also hosted a town hall-style debate between Democrat Barack Obama and Republican John McCain in 2008.

There was a far smaller audience this time around.

Only around 200 people were allowed inside, a mix of invited guests of the campaigns and the debate commission, students, the commission's production team, security, and health and safety personnel. Audience members were seated in accordance with social distancing recommendations; several empty seats separated each person or small group.

All audience members and support staff were required to undergo coronavirus testing onsite and wore colored wristbands as evidence of their negative tests.

The crowd, which included a handful of Trump-supporting stars, such as Kid Rock and former golfer John Daly, was remarkably silent throughout the 90-minute debate.

During the event, dozens of protesters gathered just off campus beyond the security perimeter. One of them held a large white sign: “220,000 DEAD ... Trump FAILED US.”

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Colvin reported from Washington. Associated Press writer Pablo Martinez Monsivais in Nashville contributed to this report.