(NewsNation) — President Joe Biden has formally endorsed Vice President Kamala Harris to be the Democratic presidential nominee after announcing the end to his reelection bid Sunday.

“Today I want to offer my full support and endorsement for Kamala to be the nominee of our party this year. Democrats — it’s time to come together and beat Trump. Let’s do this,” Biden wrote in a social media post.

Harris is off to a fast start. She raised nearly $50 million in less than a full day after Biden’s announcement.

Still, not every Democrat has endorsed Harris. Former President Barack Obama praised Biden Sunday, but didn’t mention the party’s apparent heir to the nomination.

“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,” a person familiar with Obama’s thinking told NewsNation.

The decision to end his 2024 campaign comes after growing pressure from Democrats following his heavily criticized debate performance in late June, which left many in the party skeptical about his mental acuity.

“It has been the greatest honor of my life to serve as your President. And while it has been my intention to seek reelection, I believe it is in the best interest of my party and the country for me to stand down and focus solely on fulfilling my duties as President for the remainder of my term,” Biden wrote in a letter posted to social media announcing his decision.

What happens next?

Biden’s announcement comes just weeks before delegates are expected to convene in Chicago to formalize the party’s nominee during the Democratic National Convention.

As the 81-year-old president stepped out of the race willingly, the 3,896 delegates pledged to him are free to vote for whomever they choose at the convention. Though Biden no longer controls the delegates, his endorsement of Harris will likely carry a great deal of weight.

Despite the endorsement, any remaining candidates can now make their case to win over the delegates, who would then vote for the nominee at the convention. To win the Democratic nomination, a candidate needs to win support from a majority of the delegates.

Will Harris become the nominee?

Biden did not immediately endorse Harris in the letter announcing he was dropping out of the race, but his decision to back the vice president gives her a significant edge over the other possible candidates.

Despite consistently poor approval ratings, Harris still has several clear advantages. She was on the winning ticket in 2020 and received millions of votes in the primaries that year.

Harris has also been campaigning in swing states for months, pushing the campaign’s agenda and serving as the face of the administration’s push for abortion access. She is also the only candidate who has access to the financial war chest the Biden-Harris campaign has amassed.

It is unclear if any other Democrat will challenge Harris for the nomination or if Democrats will push for an open convention where candidates can make their case to the public at the DNC, which begins Aug. 19 in Chicago.

Harris polling numbers

According to the latest Decision Desk HQ poll, former President Donald Trump is leading Harris 47.4% to 45.4%.

Before he dropped out, Biden was trailing Trump by about 2.5 points in a head-to-head. However, since the debate, Trump gained 2 points on Biden, while the president’s averages decreased by 0.1 points.

Since the debate, Harris is up nearly 5 points while Trump gained 0.4 points in a head-to-head matchup.

Harris’ favorability rating is similar to Biden’s but the share of Americans who have an unfavorable view of her is lower than the president’s.

A recent AP-NORC Center for Public Affairs Research poll found about 4 in 10 U.S. adults have a favorable opinion of Harris, while about half have an unfavorable opinion. There are more Americans with a negative view of Biden: approximately 6 in 10.

Continuing coverage from NewsNation:

• What happens to Biden’s campaign cash?
• Who could be Harris’s running mate?
• How replacing Biden will actually work
• Trump, Harris, Kennedy not the only presidential candidates
• Harris vs. Trump vs. RFK Jr.: How policies compare
• RFK Jr. criticizes Harris, Biden and Trump after election shakeup
• Gov. Newsom endorses Kamala Harris: ‘Tough. Fearless. Tenacious.’
• Kamala Harris campaign raises $49.6M in first day: ActBlue
• Harris praises Biden, honored by his endorsement
• What to know about Kamala Harris
• Former President Trump reacts to Biden leaving race
• Obama praises Biden’s decision to leave 2024 race, doesn’t endorse Harris
• Rep. Dean Phillips calls for competitive Dem nomination process