What Are the Rules for Tonight’s Debate? (Plexiglass Is Allowed, for One)

There usually isn’t much drama about the seating arrangements at vice-presidential debates.

But what would 2020 be without a little back-and-forth over how much of the same air is shared by Vice President Mike Pence and Senator Kamala Harris of California?

This week, as the scope of the White House coronavirus outbreak became clear — with positive tests now for President Trump, Melania Trump and at least eight aides, along with his campaign manager, the Republican National Committee chairwoman and three Republican senators — Mr. Pence’s aides have publicly mocked Ms. Harris for seeking protection from the air breathed out by the vice president during Wednesday’s debate at the University of Utah in Salt Lake City.

The Commission on Presidential Debates will allow Ms. Harris and the debate’s moderator, Susan Page, the Washington bureau chief for USA Today, to surround themselves with plexiglass shields. Mr. Pence’s aides at first suggested he would not use one but on Tuesday night told the commission he would.

There remained disgruntlement among the Harris camp about Mr. Pence’s exposure to Katie Miller, his press secretary. Ms. Miller’s husband, Stephen Miller, Mr. Trump’s top speechwriter and a policy aide, tested positive for the virus on Tuesday.

Ms. Miller, who had the coronavirus earlier this year, left Salt Lake City on Tuesday, after the commission prohibited her from attending the debate. On Monday, she had mocked Ms. Harris’s demands for a plexiglass shield.

“If Senator Harris wants to use a fortress around herself, have at it,” Ms. Miller told Politico.

Ms. Harris’s aides said the senator would participate in the debate.

“Senator Harris will be at the debate, respecting the protections that the Cleveland Clinic has put in place to promote safety for all concerned,” Sabrina Singh, Ms. Harris’s press secretary, said late Tuesday. “If the Trump administration’s war on masks has now become a war on safety shields, that tells you everything you need to know about why their Covid response is a failure.”

Wednesday’s debate won’t be the first instance in which a Democratic candidate insisted on a physical barrier when facing a Republican who had recently been in proximity to Mr. Trump and his top aides.

On Saturday night, Jaime Harrison, the Democrat challenging Senator Lindsey Graham, Republican of South Carolina, brought his own plexiglass shield to a debate in an effort to keep himself safe from Mr. Graham’s aerosols.

Once the vice-presidential debate begins — provided both candidates actually show up — Mr. Pence and Ms. Harris will be seated 12 feet 3 inches apart, with Ms. Page seated a similar distance from them.

As at last week’s presidential debate between Mr. Trump and Joseph R. Biden Jr., there will be no handshake “or physical greeting” by the two vice presidential candidates, according to the Commission on Presidential Debates.

Mr. Pence, Ms. Harris and Ms. Page will not wear masks onstage, but everyone else in the audience will be required to do so.

“If anyone does not wear a mask, they will be escorted out,” read the protocols released this week by the debate commission.

There will be nine segments of 10 minutes each, with topics chosen by Ms. Page. She has not disclosed those topics publicly or to the campaigns.

Mr. Pence and Ms. Harris will both be tested for the coronavirus before taking the debate stage. The commission did not make clear what would happen if either of them tested positive.