Vice President Harris is bringing the 2024 campaign full circle as a referendum on President Trump. Her speech from the Ellipse at Washington, D.C., casts her opponent as “unstable,” a man out for “revenge” and “unchecked power,” a “petty tyrant” like King George III. It signals a final week to be spent rehashing claims that weakened her pitch for votes.

The night began with supporters waving American flags, singing the National Anthem, and a “USA” chant led by someone on stage. That all three have been denounced as racist by elements of the left indicates just how much Ms. Harris seeks to anchor her campaign in patriotism. She invoked the Revolution, Normandy, Selma, and Stonewall and was met with cheers..

Ms. Harris promised “joy and optimism,” aiming to uplift and unify. She was preceded on stage by “Let’s Get Loud” by the superstar Jennifer Lopez. The vice president spent most of her half-hour speech highlighting Trump’s negatives and alleged “enemy’s list.” She painted a dark future if, she said, gesturing to the White House behind her, he’s given a new lease on the Oval Office.

“Take this pudding away,” Winston Churchill once said, “it has no theme.” It’s a vexing remark explained by one of his biographers, Richard Langworth. Churchill’s son-in-law, Lord Christopher Soames, said the prime minister used the criticism for anything from soup to pudding — British slang for any dessert — that lacked “a distinctive flavor or ingredient.”

Wordsmiths often wrestle with “theme” and, on Tuesday night, it was clear that there had been too many fingers in the pudding for Ms. Harris. It recalled the memoir “What I Saw at the Revolution,” by President Reagan’s speechwriter, Peggy Noonan. In it, she illustrates how edits in “the staffing process” might have turned even the Gettysburg Address into gibberish.

The patchwork of topics sometimes made it hard for the throng to follow. At one point, Ms. Harris described the election as “a choice about whether we have a country rooted in freedom for every American or ruled by chaos and division” and was greeted by silence. A subtle motion with her hands cued the crowd that this was an applause line.

That there was a siren in the distance for the first minutes of the speech and later a red light flashing on her microphone also distracted from the message. Ms. Harris bungled a few words, but for someone who had no expectation of being at the top of the ticket, she executed her task. Yet it was an opportunity to do so much more.

One missed moment was when a man in the crowd shouted, “We love you!” More seasoned performers, including Trump, call back, “I love you, too!” Ms. Harris, however, kept her attention fixed on the teleprompter. “I promise,” she said, “I will always listen to you, even if you don’t vote for me.” Tuning her ear to that supporter would’ve made that pledge ring true.

“I will always tell you the truth,” Ms. Harris said, a line that resonated for President Carter after Watergate. Yet she said Trump would implement the Heritage Foundation’s Project 2025, which he has disavowed. She also warned that he’d impose a “20 percent national sales tax” as if it was a proposal and not spin about the supposed cost of Trump’s tariffs, some of which she and Mr. Biden kept.

Trump is alleged to have called the dead in military cemeteries “suckers and losers,” and although many with him at the time say he didn’t, that tale found its way into Ms. Harris’s script, too. With so much that Trump has said that’s ripe for the picking and documented on video, why use examples that invite partisans, fact-checkers, and Community Notes on X to muddy the point?

Ms. Harris also charged that Trump would ban abortion, outlaw IVF, and repeal Obamacare, which he insists he will not. The vice president could have noted her opponent’s denials and asked the American people if they trust him to keep his word. It would’ve bolstered her credibility and undermined his.

That the word “inflation” is on everybody’s lips but was absent from Ms. Harris’s. That was another misstep. “Now,” she said, “our biggest challenge is to lower costs.” Here, she might have benefited from staffers adding a period rather than the line that “costs were rising even before the pandemic,” since she and Mr. Biden inherited an inflation rate that was almost flat.

When Ms. Harris proposed things like “the first-ever federal ban on price gouging on groceries,” she could have advanced her cause by explaining why, in four years, she hasn’t roused Mr. Biden to get it done. The closest she came was saying, “My presidency will be different because the challenges we face are different,” as if current problems expire with Mr. Biden’s term.

Being at the Ellipse was powerful symbolism, since it’s where Trump spoke on January 6, 2021. As dark as that day was, it was fortunate that none of the rioters fired shots. Yet Ms. Harris denounced the “armed mob” without a pointed appeal to the vast majority of Americans who found the attack repellant.

The protester shot by a Capitol Hill police officer, Ashli Babbitt, might’ve illustrated the dangers Ms. Harris sees of being deceived by Trump. This would’ve added weight to her “pledge to be a president for all Americans and to always put country above party.” A former prosecutor, she might’ve stressed that even odious criminals have certain inalienable rights that she’ll always respect.

Ms. Harris could have used her advantages at the Ellipse to much better effect. What Americans got instead were murky promises for a better future and a less than forthright picture of the past. It will be up to those who have not yet voted to decide if they like the pudding she served or if — with all its faults — they’d like another helping of Trump.