The good news for Senator Kamala Harris of California is that all the political ingredients are there. Her campaign launch in Oakland remains the largest rally of any Democratic candidate this year, her Senate committee videos go viral and she ignited the most talked-about debate moment to this point, when she confronted the front-runner, Joseph R. Biden Jr., regarding his Senate record on school integration.
The downside: Even with those head-turning moments, she is currently polling closer to the bottom rung of Democratic candidates than she is to the top tier in national surveys.
Ms. Harris’s summer dip places additional pressure on her performance at the third Democratic debate in Houston, as surrogates, donors and even some supporters are looking for her to recapture the magic that initially won them over.
Many of her campaign advisers contend there is no cause for panic at the moment, pointing to the calendar — and the four-and-a-half months between Thursday and the Iowa caucuses. Others push back on the idea that the primary has become a three person race between Mr. Biden, Senator Elizabeth Warren of Massachusetts and Senator Bernie Sanders of Vermont.
Jess Morales Rocketto, the political director for the National Domestic Workers Alliance who worked on Hillary Clinton’s 2016 campaign, said that, in her view, Ms. Harris represents what the party really wants to be and the debate is a crucial moment for the senator to make that clear.
“Voters and operatives, they want to make her their candidate,” she said. “They haven’t yet because she needs to show some more work to make that happen.”
Representative Marcia Fudge, an Ohio Democrat who has endorsed Ms. Harris, said she feels confident about her current position. Ms. Fudge expects the California senator to go on the attack in this debate because “the timing is right,” she said.
“This debate matters in particular because people don’t start paying attention until after Labor Day,” Ms. Fudge said. “Now every day people are starting to pay attention, so this is an important one.”
In the last week, both the promise and pitfalls of Ms. Harris’s campaign were on display, a microcosm of a campaign that has been defined by both high points and inconsistency. On Monday, she issued a sweeping criminal justice plan, which won her plaudits from progressive activists who had been critical of her reform record in California. But the release was somewhat muddled, as Ms. Harris had to spend the weekend apologizing for a video from an event where she seemed to laugh with an audience member who referred to the president using a mental health slur.
For some, Ms. Harris’s up-and-down summer is simply a byproduct of her own success, after an impressive debut and early fund-raising numbers created artificially high expectations she was never going to immediately meet. However, despite Ms. Harris being in the Senate since 2017, her advisers point out that she came into the race without a firm national presence and is the highest-polling Democrat from that position.
“People want to know what makes you tick,” Ms. Fudge said, relaying what she has personally told Ms. Harris. “They want to know what your values are, where you come from. That’s the huge issue.”
Ian Sams, Ms. Harris’s spokesman, said in a statement that Democrats should expect Ms. Harris to “take on Donald Trump directly” in the debate, and “make the connection between his hatred and division and our inability to get things done for the country.”
In private discussions and in donor calls, Ms. Harris’s team has acknowledged the need to better define her policy message and separate herself from her Democratic rivals. They also, particularly after her success in the first debate, have stressed to Ms. Harris that voters respond positively when she leans into her biography as a child of immigrants with a barrier-breaking career.
In an interview last week with The New York Times, Ms. Harris appeared unfazed by the fluctuations of the summer or the pressure to have another well-received debate performance.
In recent weeks, the California senator has tried to differentiate her policy message from Democratic rivals — offering her own plans on health care, climate change and criminal justice reform. She has also noticeably eradicated go-to phrases like “we need to have that conversation” from her public vocabulary, after criticism she seemed too cautious.
“Maybe I’ve made it more clear, but I’ve been clear the whole time,” Ms. Harris said of her policy vision. “I’ve always thought and talked about what wakes people up in the middle of the night.”
Still, at times, Ms. Harris’s attempts to occupy a pragmatic middle ground between progressive firebrands and old-school Democratic moderates can land in awkward ways. In late July, she said “I’m not trying to restructure society,” but in recent weeks she has released a criminal justice plan that would overhaul prisons and police practices, and embraced the possible elimination of the Senate filibuster to pass the Green New Deal.
“I plan on restructuring things in a way that will address those things that wake people up in the middle of the night,” Ms. Harris clarified last week. “That’s the consistent through line from the beginning. And frankly, even before I ran, I’ve always thought about it around that kind of metaphor.”
Mr. Sanders and Ms. Warren often target Wall Street corporations as the root cause of people’s problems, and Mr. Biden has singled out President Trump as a unique existential threat. When asked what she views as the root cause of societal problems, Ms. Harris said leaders do not see and understand the tangible hardships of working families.
“It is not about some textbook stuff. It is not some intellectual stuff. It’s not some ideological stuff,” she said. “It literally is, what is that person experiencing?”
“So maybe it’s my life experiences,” Ms. Harris added. “But these aren’t intellectual things for me. ‘What keeps people up at night?’ — those have had a profound impact, a profound effect, on me.”
It is this type of self-assuredness that supporters hope they will see from her on the debate stage. Some sounded almost giddy that Ms. Harris was not likely to be a primary focus of either the moderators or her opponents. Instead, they said, she would have a prime opportunity to forcefully remind the country that there is a reason people have been whispering about her running for president since she arrived in Washington.
Leah Greenberg, the co-executive director of the advocacy group Indivisible, said she still believes Ms. Harris can win over progressive voters, but it would require her embracing the language of systemic reform — which Ms. Harris has rejected in the past.
“We’ve been really pleased to see her coming forward on climate change and on criminal justice,” Ms. Greenberg said. “But it does feel like she needs to talk about what is the overarching vision that connects those pieces, which are really about significant societal change and structural reform.”
Aimee Allison, founder and president of She the People, the black women’s organization that held a presidential forum this year that included Ms. Harris, said a generous amount of good will still exists for her candidacy. However, the campaign has — to this point — been defined by a series of “one step forward, two step back moments,” she said.
“People want a sense of political courage,” Ms. Allison said.
She offered Ms. Harris a succinct pre-debate message: “She better come correct.”