Kamala Harris is locking down support. Any Democrat who wants to rip the nomination from her faces a steep climb.

Kamala Harris has a host of advantages as vice president that other Democratic presidential hopefuls would not.

• Vice President Kamala Harris moved quickly to lock down major support for her presidential bid.
• President Joe Biden threw his support behind her after he made the shocking decision to drop out.
• Harris already has access to a $91 million war chest, among other advantages.

Big-name Democrats and outside groups moved quickly on Sunday to help Vice President Kamala Harris lock down the party's nomination after President Joe Biden's seismic decision to drop out of the 2024 race.

Following Biden's endorsement, the president's reelection campaign committee rebranded itself to "Harris for President," handing her the keys to a $91 million war chest. Other Biden-linked groups changed their affiliation as well. Unless a wealthy Democrat cut their own campaign a giant check, it's unlikely anyone could match that massive amount of money right of the gate.

It remains to be seen if Harris will avoid a high-profile challenger. Biden can direct his delegates to support her, but officially the group of more than 4,000 Democrats are not permanently bound to his wishes.

Within a few hours, Harris' list of supporters included some of the biggest names in the Democratic Party — posing another sizable bulwark to any challenger. The vice president's endorsements now include everyone former President Bill Clinton to EMILY's list, an outside group aimed at electing women in favor of abortion rights.

"Now is the time to support Kamala Harris and fight with everything we've got to elect her," President Clinton and former Secretary of State Hillary Clinton said in a joint statement. "America's future depends on it."

The Congressional Black Caucus' political arm, which had remained behind Biden even as more Democrats tried to drive him out of the race, also lined up behind the vice president. Rep. Nanette D. Barragán of California, chair of the Congressional Hispanic Caucus, also endorsed Harris.

Harris has also lined up powerful women behind her. Hillary Clinton, the first woman to become a major party's presidential nominee, is behind Harris. So too is Sen. Patty Murray of Washington, a member of Senate leadership and third in the line of succession to the presidency.

"I am behind Kamala Harris one-hundred percent — she is exactly the the woman we need to prosecute the case against Donald Trump, save American democracy, lead the fight to restore abortion rights, and build an economy that puts working people — not billionaires — first," Murray, who is also president pro tempore of the Senate, said in a statement.

Not everyone was quick to line up behind her. Former President Barack Obama indicated that he supported an open-primary process. It remains to be seen how such a process will unfold since the Democratic primaries have concluded. The party's national convention is also set to to start in less than a month in Chicago.

"We will be navigating uncharted waters in the days ahead. But I have extraordinary confidence that the leaders of our party will be able to create a process from which an outstanding nominee emerges," Obama said in his lengthy statement which praised Biden's decision to step aside.

A source familiar with Obama's thinking said the former president thought it best to remain on the sidelines so he could help bring the party together in the event of hard feelings after the process.

"Just like he did in 2020 once Joe Biden earned the nomination, President Obama believes he will be uniquely positioned to help unite the party once we have a nominee, lift up that candidate, and do everything he can to get that candidate elected in November," the unnamed source told NBC News.

Fellow Californian, former House Speaker Nancy Pelosi, also didn't address Harris' future in her statement. Pelosi was widely perceived as helping to orchestrate that push that led to Biden bowing out.

Leaders of the AFL-CIO, part of a labor wing that have been staunch Biden allies, repeated its past support of the Biden-Harris ticket, but stopped short of a full endorsement of Harris.

Democrats' gamble has shaken up the race, but former President Donald Trump could still reclaim the White House. No one has ever seen the type of 100-day sprint that will now take place before Election Day.

Beyond seeking to upstage the first woman vice president, other ambitious Democrats would have to raise their national profile in a way Harris does not. Such an introduction is an even greater obstacle, considering that Trump is perhaps the most known figure in modern politics. While no Democrat would ever openly admit to it, if Harris were to falter it could open up the 2028 race to a greater degree. In contrast, besting Harris and falling to Trump would stain a rising star's status.

Harris' potential nomination is far from a political panacea for nervous Democrats. Republicans have made it clear they will try to tie her candidacy to the least popular parts of Biden's record, particularly on immigration.

One of the biggest sources to watch in the days ahead will be the Democratic National Committee. As leader of his party, Biden pushed the DNC to rubber stamp his plan to shake-up the primary calendar. Democrats also didn't hold any primary debates as Biden avoided any major challengers.

The DNC was plowing ahead with a controversial plan to name Biden the nominee before the August convention. As of now, the virtual vote was not expected to occur before August 1. If the virtual vote moves forward, ambitious Democrats will face any even tighter window to organize opposition to Harris' nomination.