Vice President Harris now appears to be the odds-on favorite to be the Democratic nominee for president this year, after picking up endorsements from prominent elected officials and party apparatchiks alike. President Biden’s delegates, who are no longer bound to any candidate, will have the final say. 

It takes 1,986 pledged delegate votes to become the Democratic nominee for president, out of the 3,949 that are allocated. Mr. Biden won more than 3,900 of those delegates during the primaries, and 37 votes went to the “uncommitted” campaign — a coalition of voters who sought to send pro-ceasefire delegates to the convention to protest the war at Gaza.

The Trump campaign had been hoping for a messy convention for Mr. Biden with left-wing protesters agitating in the streets. Suddenly, though, President Trump’s advisers are saying publicly that they are concerned now that the party is coalescing around a new candidate who could prove more fierce than the sitting president. 

“During this entire term, Kamala Harris — as well as every other Democrat in Washington, sat by and did NOTHING,” top Trump advisers Susie Wiles and Chris LaCivita wrote in an email to reporters. “They are all just as complicit as Biden is in the destruction of our once-great Nation, and they must all be thrown out of office. Kamala Harris is just as much of [a] joke as Biden is.”

In a statement released Sunday, the advisers began trying to tie Mr. Biden’s weaknesses to Ms. Harris, though at 59 years old, the vice president clearly does not have the apparent physical and mental frailties that were causing the Biden campaign to implode. 

The rallying around Ms. Harris has been rapid, and could prevent dissent at Chicago, where in just a few weeks Democrats will gather for the nominating convention. Only two senators — Joe Manchin, who is no longer a Democrat, and Peter Welch — have said there should be an open process for choosing the next nominee.

Polling has shown that Ms. Harris is not running away with the general election but is merely hanging on. Even that is something Mr. Biden was unable to do. Polling suggests choosing the right running mate — Pennsylvania’s governor, Josh Shapiro, polls indicate, or other swing state figures — helps her pull ahead of Trump in key states. 

Ms. Harris not only kept her most powerful potential challengers on the bench by winning the endorsements of Governors Prizker and Newsom and Mr. Shapiro, but she’s making inroads with delegates as well. An “uncommitted” delegate from Massachusetts, state representative Christopher Worrell, says he will be casting his ballot for Ms. Harris, even though he planned to vote against Mr. Biden on the first ballot.

“As an elected delegate and alternate to the Democratic National Convention, we are formally committing our support to Vice President Kamala Harris to be the Democratic Nominee,” Mr. Worrell and his brother, Boston city councilor Brian Worrel, who is an alternate, said in a statement. “We look forward to going to Chicago to cast our votes for Kamala Harris and working each and every day to ensure she is the next President.”

The Biden delegates are also lining up behind the vice president, further cementing her position as the presumptive nominee. According to Axios, the 159-member strong Pennsylvania delegation voted unanimously on Monday to support Ms. Harris at the United Center next month. A delegate tracker set up by the Associated Press finds that by Monday, Ms. Harris already had the support of half of the delegates needed to win the presidential nomination. 

In Congress and in governors’ mansions across the country, Ms. Harris has won allies who are heavy-hitters in their own delegations to the convention. Speaker Pelosi, arguably America’s most talented vote-counter, announced her support for Ms. Harris on Monday. They are both from San Francisco, on the Coast.

“It is with immense pride and limitless optimism for our country’s future that I endorse Vice President Kamala Harris for President of the United States,” the speaker emerita wrote. The governors of Massachusetts, Illinois, Maryland, New Jersey, and California — five delegate-rich states that are home to many of the party’s biggest donors — are also backing the veep. 

On the money front, Ms. Harris has gained a huge boost during the first 24 hours of her campaign. Her campaign says it has raised more than $81 million since Mr. Biden abandoned his campaign and endorsed Ms. Harris — making it the largest single-day fundraising haul in American history. That excludes funds that were already raised under Mr. Biden.

According to a fundraising tracker for the Democratic money-raising software ActBlue, the platform processed nearly $70 million in donations to Democrats on Sunday alone. On Monday, Politico reported that major party donors had committed a combined $150 million to an outside spending group that will support Ms. Harris called Future Forward — a political action committee that already has $122 million on hand for the campaign. 

Despite the fact Ms. Harris has seemingly locked up all institutional support in the Democratic Party, including some of the country’s biggest labor unions, it is ultimately the decision of the delegates to choose the nominee. Mr. Biden does not have to “release” his delegates to Ms. Harris under party rules. That contrasts with, say, the GOP. Republican delegates who would have been forced to vote for their candidate on the first ballot had that candidate — like Governor Haley — not released them to vote for whomever they choose. 

Under the Democratic convention’s rules, delegates must vote their conscience when selecting a nominee for the party. That person need not be whom they were sent to the convention to support.

“Delegates elected to the national convention pledged to a presidential candidate shall in all good conscience reflect the sentiments of those who elected them,” the convention rules state. Mr. Biden’s endorsement of Ms. Harris for the nomination will likely carry weight with those more than 3,900 delegates who are being sent to Chicago to support him. Even if more than 1,000 of them were to defect, Ms. Harris would win the presidential nod. 

The convention will be presided over by two party insiders — the chairman of the Democratic National Committee, Jamie Harrison, and Democratic strategist Minyon Moore, who will serve as chairwoman of the convention. The role of convention chairman is typically handed out to a party insider who is close with the rest of the leadership team. In 2016, the party chairwoman, Congresswoman Debbie Wasserman-Schultz, tapped her friend and colleague Congresswoman Marcia Fudge, to preside over the convention. 

This year, Ms. Moore, who is a confidante of both the Clintons and Mr. Biden, will serve as chairwoman of the gathering. “I am grateful to the team members who have already been working hard, and know that through their work, and the strong team we continue to build, that this convention will be a success,” Ms. Moore, a Chicago native, said in a statement to Politico when she was selected last year. She served as White House political director for President Clinton and was an advisor to the Biden 2020 campaign.