Judging by her performance on “Saturday Night Live,” Vice President Harris is in good spirits as the race for the presidency enters its final days. It’s unfortunate that when the laughter recedes, legal questions about the unoriginal cameo may overshadow an otherwise sunny moment in a dark election year.

On September 19, the executive producer of “Saturday Night Live,” Lorne Michael, told the Hollywood Reporter that neither Ms. Harris nor two-time host President Trump would appear. “You can’t bring the actual people who are running on,” he said, “because of election laws and the equal time provisions.” So many “minor candidates,” he added, make cameos “really complicated.”

Why Mr. Michael would make such a declaration only to reverse it five weeks later — and why Ms. Harris would accept — is a question for them. Campaigns have raised objections over less and here, a Trump complaint to the Federal Election Commission can cite the sketch mocking him that preceded Ms. Harris’s and Mr. Michael’s own words.

It’s possible that Mr. Michael offered to feature all candidates along with Trump and they declined. Barring that or some loophole the producer found, the vice president must have felt the chance to reach the “Saturday Night Live” audience was worth the risk of a fine long after the election.

After the Trump sendup and an introduction, Ms. Harris appears. She is beaming, looking more at ease than she does behind a podium. The woman who portrays her for the 50-year-old sketch show, Maya Rudolph, sits opposite through a makeup mirror ringed with lights, dressed in an identical brown suit.

“I wish I could talk to someone who’s been in my shoes,” Ms. Rudolph says as the candidate, “you know, a black South Asian woman running for president, preferably from the Bay Area.” It is then that Ms. Harris appears and says, “You and me both, Sista.” Cheers and applause wash away the words.

Both women seem overwhelmed by the moment. It’s not easy for even trained performers to know what to do with themselves when an audience erupts. Ms. Harris sat and absorbed the adulation for the full 28 seconds, seeming humbled and energized. It was, as they say, “a good look.”

When the applause subsides, Ms. Harris repeats the “Sista” line that had been obscured. “You’ve got this,” she tells her reflection. “Because you can do something your opponent cannot do: You can open doors.” Ms. Rudolph said she understands it to be an allusion to Trump missing the handle on the door of a garbage truck.

Next Ms. Rudolph did her impression of Ms. Harris’s laugh. “I don’t really laugh like that, do I?” the vice president asks. “A little bit,” Ms. Rudolph says. It was almost the identical question Senator Clinton asks her doppelganger in 2008, and the déjà vu doesn’t end there.

An impressionist speaking to the person they’re portraying through a dressing room mirror was the format of a 2015 skit on “The Tonight Show,” with the host, Jimmy Fallon, speaking to Trump as Trump. Since Mr. Fallon is a veteran of “Saturday Night Live,” and both shows are on NBC, it’s possible that they decided it would be safe to recycle the idea.

The repeats saved time on what looked like a last-minute booking, with Ms. Harris’s plane only rerouting for New York hours prior to taping. It’s odd, however, that a show born out of “The Second City” comedy school of improvisation couldn’t come up with something original even on short notice.

In any event, wordplay follows with Ms. Harris’s first name and a desire that victory would settle people on the vice president’s preferred pronunciation. The sketch ends with Ms. Harris asking if Ms. Rudolph happens to be registered to vote in the key state of Pennsylvania, which she is not.

The two women had such electric chemistry, the 143-second sketch seemed longer. Ms. Harris now joins President George H. W. Bush and Senators Clinton and Bob Dole who appeared on “Saturday Night Live” with their impressionists. Attorney General Reno also appeared with her impersonator, Will Ferrell, at her “dance party.”

“It’s so important to laugh at ourselves,” Reno said in a commencement address at the University of California, Berkeley, in 2001, “and more importantly, to laugh with each other. Laughter is the great leveler. It puts attorneys general and Will Ferrell on the same level.”

Reno’s words ring true today. As contentious as the 2000 campaign for president was between President George W. Bush and Vice President Gore, at times, they seemed to be competing not only for votes, but to see who could make a better joke at his own expense.

What Americans couldn’t have known then was that Mr. Gore would retract his concession on election night, leading to weeks of lawsuits. When Mr. Bush prevailed, some Democrats objected to certifying his Electoral College victory, calling him illegitimate and arguing that the vote had been rigged in Florida.

Since the vice president is president of the Senate, it fell to Mr. Gore to certify the victory of Mr. Bush, who he had beaten in the popular vote. The Washington Post wrote that like President Nixon, who’d certified President Kennedy’s victory after losing to him in 1960, “Gore tried to bring ‘grace and humor’ to the proceedings.”

No one knows what will happen this Election Day. We do know that America is in a much more precarious position than 1960 or 2000, with deeper divisions and higher stakes. “Saturday Night Live” might have done a service by giving both candidates an opportunity to laugh at themselves and inviting the country to laugh with them.

By having only Ms. Harris, Mr. Michaels blew that chance to unify, but the vice president handled her star turn with grace and humor. They’re qualities that will serve her well if she wins on Tuesday, and ones that she’ll need even more if, come January, she must follow Nixon and Mr. Gore and preside over the certification of the man who beat her.