What Are the Rules for the Vice-Presidential Debate Tonight?

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.