Within minutes of President Joe Biden's historic decision to step aside from the Democratic ticket in November's election, members of his party praised him for choosing to pass the torch to a younger nominee.

"Joe Biden has not only been a great president and a great legislative leader but he is a truly amazing human being," said Senate Majority Leader Chuck Schumer, D-N.Y. "His decision of course was not easy, but he once again put his country, his party, and our future first. Joe, today shows you are a true patriot and great American."

Biden, who faced numerous calls to step down after his shaky performance against Republican presidential candidate Donald Trump in last month's debate, quickly offered his full-throated endorsement to Vice President Kamala Harris. 

Harris in turn praised the president in a statement, saying his "remarkable legacy of accomplishment is unmatched in modern American history, surpassing the legacy of many Presidents who have served two terms in office." She called his decision to step aside a "selfless and patriotic act."

She wrote of first getting to know Biden through his son Beau when they were both serving as attorneys general of their respective states. 

"As we worked together, Beau would tell me stories about his Dad. The kind of father—and the kind of man—he was," Harris said. "And the qualities Beau revered in his father are the same qualities, the same values, I have seen every single day in Joe’s leadership as President: His honesty and integrity. His big heart and commitment to his faith and his family. And his love of our country and the American people."

Harris accepted Biden's endorsement and said she "will do everything in my power to unite the Democratic Party—and unite our nation—to defeat Donald Trump and his extreme Project 2025 agenda."

“We have 107 days until Election Day. Together, we will fight. And together, we will win,” she added.

But while Democrats touted Biden's accolates, Republicans condemned the incumbent and urged him to resign immediately.

"Let me be clear, if Joe Biden can’t run for re-election, he is not capable of serving as president for the next six months and needs to resign today," said Florida Sen. Rick Scott, who helmed the GOP's unsuccessful efforts to reclaim the Senate in the 2022 midterm elections.

Here's how major figures reacted to Biden's decision to step aside:

Naomi Biden, the president's granddaughter and the daughter of Hunter Biden, expressed pride for her grandfather's accomplishments.

"I’m nothing but proud today of my Pop, our President, Joe Biden, who has served our country with every bit of his soul and with unmatched distinction," she wrote on social media. "Not only has he been—and will continue to be—the most effective president of our lifetime, but he has likely already cemented himself as the most effective and impactful public servant in our nation’s history."

"He has been at the center of, and had a material impact on, literally every single major issue that our country and world has faced for 50 years," she added. "Our world is better today in so many ways thanks to him. To the Americans who have always had his back, keep the faith. He will always have ours."

Hunter Biden, the embattled son of Joe Biden who has been at the center of a House Republican-led impeachment inquiry into the president, expressed his love for his father in a statement obtained by ABC News. 

"For my entire life, I’ve looked at my dad in awe," said Hunter Biden. "How could he suffer so much heartache and yet give so much of whatever remained of his heart to others? Not only in the policies he passed, but in the individual lives he’s touched. “Over a life time I have witnessed him absorb the pain of countless everyday Americans who he’s given his personal phone number to, because he wanted them to call him when they were hurting. When their last hopes were slipping through their hands."

"That unconditional love has been his North Star as a President, and as a parent.  He is unique in public life today, in that there is no distance between Joe Biden the man and Joe Biden the public servant of the last 54 years.“I’m so lucky every night I get to tell him I love him, and to thank him. I ask all Americans to join me tonight in doing the same," he concluded. Thank you, Mr. President. I love you, Dad.”

First lady Jill Biden, the president's wife of 47 years, simply posted a heart emoji as she shared her husband's letter.

Democrats, even those who called on Biden to step down from the ticket, praised his bonafides as a leader and expressed gratitude for his service.

In a lengthy statement, former President Barack Obama went into detailed praise for his former vice president, both for his character and his policy accomplishments.

"Sixteen years ago, when I began my search for a vice president, I knew about Joe’s remarkable career in public service. But what I came to admire even more was his character — his deep empathy and hard-earned resilience; his fundamental decency and belief that everyone counts," Obama wrote. "Joe understands better than anyone the stakes in this election — how everything he has fought for throughout his life, and everything that the Democratic Party stands for, will be at risk if we allow Donald Trump back in the White House and give Republicans control of Congress."

"I also know Joe has never backed down from a fight. For him to look at the political landscape and decide that he should pass the torch to a new nominee is surely one of the toughest in his life. But I know he wouldn’t make this decision unless he believed it was right for America," he continued.

Obama did not endorse Harris, writing that the party "will be navigating uncharted waters in the days ahead," but expressed "extraordinary confidence that the leaders of our party will be able to create a process from which an outstanding nominee emerges."

Former President Bill Clinton and 2016 nominee Hillary Clinton, the former first lady, U.S. Senator and secretary of state, hailed Biden's decades of service to the country.

"President Biden has capped his extraordinary career of service with a Presidency that has lifted America out of an unprecedented pandemic, created millions of new jobs, rebuilt a battered economy, strengthened our democracy, and restored our standing in the world," the Clintons said in a joint statement. "By any measure, he has advanced our founders’ charge to build a more perfect union and his own stated goal of restoring the soul of our nation. We join millions of Americans in thanking President Biden for all he has accomplished, standing up for America time and again."

House Democratic Leader Hakeem Jeffries called Biden "one of the most accomplished and consequential leaders in American history."

"In less than one term, he rescued the nation from a once-in-a-century pandemic, brought the economy roaring back from the brink of recession, enacted consequential legislation for everyday Americans and saved our democracy by defeating the Insurrectionist-in-Chief," said the New York Democrat. "America is a better place today because President Joe Biden has led us with intellect, grace and dignity. We are forever grateful."

Speaking exclusively to Spectrum News NY1 on Sunday, Jeffries said he had a "private conversation" with Biden earlier in the day, but did not detail what they discussed.

"He is a tremendous patriot, a tremendous president who's done an amazing job on our behalf over the last three-and-a-half years," Jeffries said. "America is better off today because of the incredible leadership of President Joe Biden."

He did not answer a shouted question from Spectrum News' Kelly Mena about if he supports Harris as the Democratic nominee.

Former House Speaker Nancy Pelosi, a leading voice in recent weeks amid the calls for Biden to step aside, praised his leadership without offering a choice for his successor.

"President Joe Biden is a patriotic American who has always put our country first. His legacy of vision, values and leadership make him one of the most consequential Presidents in American history," the California Democrat said in a post on social media. "With love and gratitude to President Biden for always believing in the promise of America and giving people the opportunity to reach their fulfillment. God blessed America with Joe Biden’s greatness and goodness."

And former Vice President Al Gore said on social media that " Biden has been — and is — an exceptional leader."

"I know that he is not done delivering for the American people and will continue to serve this nation with wisdom and dignity in the coming months. In paving the way for a new generation of leadership, President Biden’s decision is a fitting testament to his profoundly consequential career," Gore wrote. "I applaud his selfless decision."

Texas Rep. Lloyd Doggett, the first House Democrat to call Biden to withdraw, said in a statement that "once again President Biden comes through for America, putting country over ego in a way that Donald Trump never could." He acknowledged Harris as the "leading candidate," but said the party should "be open to all talented individuals who wish to be considered."

Michigan Gov. Gretchen Whitmer, a candidate who has been floated to replace Biden and a key member of his campaign, said that her "job in this election will remain the same: doing everything I can to elect Democrats and stop Donald Trump."

"President Biden is a great public servant who knows better than anyone what it takes to defeat Donald Trump," Whitmer, who represents a key battleground state, said in a statement on social media. "His remarkable work to lower prescription drug costs, fix the damn roads, bring supply chains home, address climate change, and ensure America’s global leadership over decades will go down in history."

"My job in this election will remain the same: doing everything I can to elect Democrats and stop Donald Trump, a convicted felon whose agenda of raising families’ costs, banning abortion nationwide, and abusing the power of the White House to settle his own scores is completely wrong for Michigan," she continued"

"Joe Biden has earned his place among the best and most consequential presidents in American history," said Transportation Secretary Pete Buttigieg, who challenged Biden for the 2020 nominationa nd is viewed as a possible contender for a future Democratic nomination, wrote on social media. "I am so proud to serve under his leadership, and thankful for his unwavering focus on what is best for our country."

Pennsylvania Gov. Josh Shapiro, another popular figure in a key swing state who has been floated as a possible part of a replacement 2024 ticket, called Biden "a patriot who has served our country honorably" and "one of the most consequential presidents in modern history."

"President Biden has gotten an incredible amount done to move our country forward, defend our democracy, and protect real freedom," he wrote on social media. "I am proud to work by his side and am grateful for his leadership and his unwavering commitment to delivering for Pennsylvania — the Commonwealth that raised him."

"Thank you Joe," said Andrew Yang, another 2020 hopeful who urged Biden to step aside in recent weeks.

Vermont Sen. Bernie Sanders, Biden's top rival for the 2020 nomination and a key ally during his administration who staunchly defended him from calls to step aside, praised Biden as "the most pro-working class president in modern American history."

Trump, the Republican presidential nominee in November's election, said in a post on his social media platform that Biden "was not fit to run for President, and is certainly not fit to serve - And never was!" despite decisively losing to the Democrat in the 2020 election.

"We will suffer greatly because of his presidency, but we will remedy the damage he has done very quickly," Trump said after making numerous dubious claims about Biden's mental acuity and about his accomplishments as president.

In subsequent social media posts later Sunday, Trump attempted to cast doubts on Biden's COVID-19 diagnosis, baselessly charging the Democrat used it as cover to exit the race, sought to try and move September's scheduled presidential debate from ABC News to the much friendlier Fox News, and said the Republican Party should be "reimbursed for fraud" after being "forced to spend time and money on fighting Crooked Joe Biden."

Trump's running mate, Ohio Sen. JD Vance, wrote on social media that Biden was "the worst President in my lifetime and Kamala Harris has been tright there with him every step of the way."

"Over the last four years she co-signed Biden's open border and green scam policies that drove up the cost of housing and groceries. She owns all of these failures, and she lied for nearly four years about Biden's mental capacity--saddling the nation with a president who can't do the job," Vance wrote. "President Trump and I are ready to save America, whoever's at the top of the Democrat ticket. Bring it on."

Other members of Trump's party urged Biden to resign immediately, while also seeking to make the case that Democrats forcing Biden off of the ticket after millions of primary ballots were cast is anti-democratic.

"Having invalidated the votes of more than 14 million Americans who selected Joe Biden to be the Democrat nominee for president, the self-proclaimed ‘party of democracy’ has proven exactly the opposite," said House Speaker Mike Johnson, later adding: "If Joe Biden is not fit to run for President, he is not fit to serve as President. He must resign the office immediately. November 5 cannot arrive soon enough."

"If Joe Biden is unfit to be the Democrat nominee for president, he’s unfit to be president for the rest of his term," said Oklahoma Rep. Kevin Hern. "For the good of the country, Joe Biden should resign immediately."

"The Democrats’ hypocrisy knows no bounds. The same people who spent years saying President Trump and Republicans are a threat to democracy, just pushed out the sitting president from running for re-election because they don’t think he can win," Scott, the Florida Republican, said in a statement. "Let’s be clear – Washington’s Democrat elite went around the will of Democrat voters who picked Biden to be their nominee. They think they know better than the American people and will stop at nothing to hold on to power."

House Republican allies of Trump proposed legislation in response to Biden's announcement: New York Rep. Elise Stefanik, the House GOP Conference Chair, said that on Monday she will introduce a resolution attacking her role as Biden's "border czar" -- while Republicans keep attacking Harris as Biden's "border czar," it's a misleading term; Harris was never tasked with border issues, she was tapped by Biden to address the root causes of migration -- while South Carolina Rep. Nancy Mace said she will offer a measure to call on Harris to invoke the 25th Amendment and "assume the duties as acting president."

Despite the outcry from much of Biden's opposition party, some actually offered the Democratic incumbent praise for his announcement.

"I respect President Biden’s decision to act in the best interest of the country by stepping aside in the 2024 presidential election," said Alaska Sen. Lisa Murkowski, one of the few Republicans in Congress not to endorse Trump.

"I respect President Biden for his decades of public service," said Larry Hogan, the former Maryland governor and current candidate for U.S. Senate. "I believe he made the right decision for his family and the country. These are dangerous and unprecedented times. He should be commended for putting the country ahead of personal ambition."

Former Wyoming Rep. Liz Cheney, a prominent Trump critic who served on the House panel investigating the Jan. 6 attack, lauded Biden for his decision and his years of service to the country.

"The framers of our Constitution knew that our republic would endure only if our presidents have the character and honor to put duty ahead of self interest," Cheney said on social media. "President Biden deserves our gratitude for his decades of service to our nation and for his courageous decision today."

So did Cheney's fellow member of the House Jan. 6 committee, former Illinois Rep. Adam Kinzinger, who recently endorsed Biden (and saw his former chief of staff join the Democrat's campaign to lead GOP outreach).

"Here is the difference between a man who loves his country, and one who loves himself. Joe Biden did an honorable and selfless act by stepping aside," Kinzinger said. "His legacy will be among the best. Trump cares about Trump only.  And the GOP is too scared to do what the Dems did:  tell the truth."

"Though President Biden and I have not seen eye-to-eye on a number of issues, I recognize his deep commitment to our country, and thank him for his years of service to the nation," Rep. Mike Lawler, who represents a frontline district in New York's Hudson Valley, said in a statement. "During a career that spanned 5 decades, the President committed himself to trying to better the lives of Americans, and while I disagree with his policy proposals, I appreciate his resolve and his sacrifices."

Former Vice President Mike Pence also offered praise for Biden's choice, saying he "made the right decision for our country" and thanking him "for putting the interests of our Nation ahead of his own."

"After the assassination attempt on President Trump and President Biden’s decision to end his campaign, now is a time for leaders in both parties to project calm and send a message of strength and resolve to America’s friends and enemies alike that, whatever the state of our politics, the American people are strong and our American military stands ready to defend our freedom and our vital national interests anywhere in the world," he wrote on social media.

Pence has notably not endorsed his former boss, Donald Trump.

While many of the accolades among Democrats were centered around Biden, several offered their praise for Harris. While not officially the nominee, Biden quickly offered his former running mate his emphatic endorsement on Sunday.

"My very first decision as the party nominee in 2020 was to pick Kamala Harris as my Vice President. And it’s been the best decision I’ve made," Biden said. "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."

Others echoed Biden's call, pushing for unity behind the vice president. In their statement praising Biden, the Clintons joined him in endorsing Harris, pledging to do “whatever we can to support her.”

“Now is the time to support Kamala Harris and fight with everything we’ve got to elect her. America’s future depends on it,” the Clintons wrote.

Hillary Clinton wasn't the only former Democratic candidate to back Harris; John Kerry, the 2004 Democratic candidate, former secretary of state under Barack Obama and Biden's former special envoy on climate, offered his support on Sunday.

"President Biden deserves the gratitude of every American for his extraordinary presidency," Kerry wrote on social media. "History will record that, with the thinnest imaginable majority in the Senate, he  achieved a domestic agenda unseen since the New Deal, and made America lead like America again on the world stage. I know how difficult today’s selfless decision must have been for someone who spent his entire life in service to country.

"He’s spoken up for democracy, he’s spoken out for fundamental freedoms, and his voice will not be silenced," he continued. "In fact, his voice now will be absolutely critical in helping our country crystallize a clear choice in 2024. For democracy, alliances, economic fairness, and the future of our planet, now is the time to listen to the only person who has ever beaten Donald Trump, and join with President Biden in every effort to make Vice President Harris the next President of the United States. No citizen of good conscience should stay on the sidelines."

South Carolina Rep. Jim Clyburn, a key House Democrat whose endorsement was crucial to Biden's primary victory in 2020, offered Harris his backing on Sunday.

"I echo the good judgment [Biden] demonstrated in selecting Vice President Harris to lead this nation alongside him, and I am proud to follow his lead in support of her candidacy," Clyburn said. 

A handful of influential Democratic groups in Congress offered their quick endorsement to Harris on Sunday, including the powerful Congressional Black Caucus, who were staunch supporters of Biden.

"The Congressional Black Caucus PAC joins President Biden in fully supporting Harris as our party's nominee," the group said in a statement, adding: "She will do an excellent job as President of the United States."

"Today, with his decision to not seek reelection in 2024, he has once again put the party and country first. We are eternally grateful for his decades of service and for taking on the fight to restore the soul of our nation," New Hampshire Rep. Annie Kuster, the chair of the center-left New Democrat Coalition, told Punchbowl News, adding that Harris has her "full-throated endorsement."

"Millions of Americans cast their ballots for Joe Biden and Kamala Harris in the primary," said Washington Rep. Pramila Jayapal, the chair of the House Progressive Caucus. "Vice President Harris has proven time and time again that she can prosecute the case against Donald Trump and campaign vigorously for Democrats down the ballot. She will mobilize and energize our base to re-engage and ensure that we turn out every single voter across the country and deliver victory in November."

"Thank you for your dedicated service President @JoeBiden," said Massachusetts Rep. Ayanna Pressley, a prominent House progressive. "And @KamalaHarris I’m all in, let’s go. #BlackWomenLead."

"Thank you, Mr. President. This was the president’s decision to make and I’m grateful for his years of service to our country," said Minnesota Rep. Ilhan Omar, another progressive. "Thrilled to support @KamalaHarris as our Democratic nominee and remain committed to working alongside her to defeat Donald Trump in November."

The Congressional Hispanic Caucus chair, California Rep. Nannette Barragán, also offered her endorsement of Harris. As did progressive Sen. Elizabeth Warren of Massachusetts, who ran against Biden and Harris in the 2020 primary.

"I endorse Kamala Harris for President. She is a proven fighter who has been a national leader in safeguarding consumers and protecting access to abortion. As a former prosecutor, she can press a forceful case against allowing Donald Trump to regain the White House," Warren wrote. "We have many talented people in our party, but Vice President Harris is the person who was chosen by the voters to succeed Joe Biden if needed.  She can unite our party, take on Donald Trump, and win in November."

Biden officials past and present also looked ahead to a November victory behind Harris.

"Now that the donors and electeds have pushed out the only candidate who has ever beaten Trump, it’s time to end the political fantasy games and unite behind the only veteran of a national campaign — our outstanding @vp , @KamalaHarris !!" said former White House chief of staff Ron Klain. "Let’s get real and win in November!"

"We’re going to win in November," said Biden-Harris campaign finance chair Rufus Gilford. "We’re going to fight even harder. And we’re going to do it for @JoeBiden."