New rules for the last rumble: Cut the mic

Good morning, NBC News readers.

The all-powerful mute button enters the debate arena, the Supreme Court weighs in on ballot counting in a key battleground state and "the Dude" announces a tough diagnosis.

Here's what we're watching this Tuesday morning.

New debate rules: Cut the mic

President Donald Trump and Joe Biden will have their microphones cut off during parts of Thursday’s final presidential debate, the Commission on Presidential Debates announced Monday.

The format of the candidates last in-person contest in Nashville, Tennessee, is a 90-minute debate broken up into six 15-minute segments on different topics. The commission said it will give Trump and Biden two minutes apiece to speak uninterrupted at the start of each segment.

The mute button is being deployed in an attempt to thwart the frequent interruptions by Trump that marred the only previous debate last month.

The commission said both microphones will be on, however, during open-discussion segments of the debate.

"One may think they go too far, and one may think they do not go far enough," the commission said in a statement about the new measures. "We are comfortable that these actions strike the right balance and that they are in the interest of the American people, for whom these debates are held."

The Supreme Court also announced a major decision Monday that may impact the outcome of the election.

In a tie 4-4 decision, the Supreme Court let stand a decision by Pennsylvania's highest court that allows election officials in the battleground state to count ballots that arrive up to three days after Election Day.

The ruling was a defeat for Republicans who said counting late ballots would inject chaos into an already complicated general election.

The tie decision in the current eight-member Supreme Court also shows how Judge Amy Coney Barrett could play a decisive role in election disputes if she is confirmed to the high court in the next two weeks.

Listen to our Into America podcast for a discussion of Barrett's record on race.

Trump ramps up rally strategy that may come with more risk than reward

"We get these massive crowds, he gets nobody and then they say we are tied," a disbelieving Trump said about Biden at a campaign event in Nevada on Sunday.

In Trump’s favored narrative of how elections are won and lost, the candidate who holds the most events with the biggest crowds wins.

Except, NBC News' Shannon Pettypiece reports, that there are no objective indications that Trump's rallies have any relation to boosting his support, there are even some suggestions that they energize his opponents' supporters as much as his own.

For example, Trump has been to Pennsylvania more than any other state since the summer, making seven trips since August. Yet in polls by Reuters/Ipsos taken over that time, Biden’s lead has grown from a 3-point advantage in mid-September to a 5-point lead by the end of the month, and a 7-point advantage as of last week.

So ramping up for more rallies may present a risky strategy with just two weeks left to Election Day.

Meantime, Lindsey Graham's challenger, Jamie Harrison, has left the Republican incumbent fighting for his political future and has put South Carolina back in play for Democrats.

Track the race: See and compare national polling averages for Trump and Biden with our Presidential Poll tracker.

Covid 'challenge trial' launched in U.K. could see healthy volunteers infected with virus

Volunteers in the United Kingdom look set to be intentionally infected with Covid-19 as part of an experimental trial that could change scientists' understanding of the virus.

The U.K. government announced Tuesday it is investing over $40 million in the first stage of what are known as "challenge trials."

These groundbreaking but controversial studies involve volunteers being injected with a potential vaccine before being given a dose of Covid-19.

But critics argue that too little is known about Covid-19 to make challenge trials safe.

"People are divided because it's an ethical conundrum," said Sue Tansey, a pharmaceutical physician who is a member of the Nuffield Council on Bioethics, an independent British watchdog.

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Plus

THINK about it

I'm a Republican voting for Joe Biden over Trump. Because I'm an American first, former chairman of the Republican National Committee Michael Steele writes in an opinion piece.

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One fun thing

After a months-long, playful spat between HBO host John Oliver and the mayor of Danbury, Connecticut, the town renamed a sewage plant in the comedian’s honor last week.

Oliver had criticized the town while discussing racial discrimination in jury selection in the state during a segment on his show in August. That led to a back-and-forth between him and the town on Facebook.

But after donning what looked like a homemade protective suit at the official sewer dedication ceremony, Oliver took a positive spin on the squabble.

"This place takes the worst that humanity can produce, and transforms it into something that we can live with," Oliver said on his show Sunday.

Thanks for reading the Morning Rundown.

If you have any comments — likes, dislikes — send me an email at: petra@nbcuni.com

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Thanks, Petra