With just over two months until the Iowa caucuses, her staff is now riven between competing factions eager to belittle one another, and the candidate’s relationship with Mr. Rodriguez has turned frosty , according to multiple Democrats close to Ms. Harris. Several aides, including Jalisa Washington-Price , the state director in crucial South Carolina, have already had conversations about post-campaign jobs.

Representative Marcia Fudge, who has endorsed Ms. Harris and is a former chairwoman of the Congressional Black Caucus, said in an interview that the senator was an exceptional candidate who had been poorly served by some top staff and who must fire Mr. Rodriguez. But she also acknowledged that Ms. Harris bore a measure of responsibility for her problems — “it’s her campaign” — and that the structure she created has not served her well.

“I have told her there needs to be a change,” said Ms. Fudge, one of several women of color who have been delivering hard-to-hear advice to Ms. Harris in recent weeks. “The weakness is at the top. And it’s clearly Juan. He needs to take responsibility — that’s where the buck stops.”

Ms. Harris declined an interview request for this article.

Mr. Rodriguez, in a statement, said: “Our team, from the candidate to organizers across the country, are working day in and out to make sure Kamala is the nominee to take on Donald Trump and end the national nightmare that is his presidency. Just like every campaign, we have made tough decisions to have the resources we need to place in Iowa and springboard into the rest of the primary calendar.”

Ms. Harris is reluctant to make a leadership change within her campaign so late in the race , some aides say , but they describe her as cleareyed about the mistakes she has made and the difficulty of her task ahead. They say she has bought into focusing on Iowa, where her campaign has structured more one-on-one settings for her to woo supporters or at least enjoy herself in otherwise difficult days.

But her troubles go beyond staffing and strategy: Her financial predicament is dire. The campaign has not taken a poll or been able to afford TV advertising since September, and it has all but quit buying Facebook ads in the last two months. Her advisers, after months of resistance, have only now signaled their desire for a group of former aides to begin a super P AC to finance an independent political effort on her behalf.