Biden started regaining ground after winning second place in the Nevada caucuses and, on February 29, 2020, he won a landslide victory in the South Carolina Democratic primary, which reinvigorated his campaign.

He was eventually chosen by Barack Obama as his running mate and won the general election as vice president of the United States, being sworn in on January 20, 2009.

[29] Dovere reported that Biden was concerned about the effect another presidential run could have on his family and reputation, as well as fundraising struggles and perceptions about his age and relative centrism compared to other declared and potential candidates.

[29] Conversely, his "sense of duty", offense at the Trump presidency, the lack of foreign policy experience among other Democratic hopefuls and his desire to foster "bridge-building progressivism" in the party were said to be factors prompting him to run.

[60] Biden subsequently finished a distant second in the Nevada caucuses held on February 22, but his campaign viewed his large support among black voters in the state as a sign of strength heading into the South Carolina primary.

[67] In early March, shortly before Super Tuesday, Pete Buttigieg and Amy Klobuchar dropped out of the race and endorsed Biden, widely perceived as attempts to slow down Sanders' momentum in the primaries.

[71] On the Super Tuesday primary elections on March 3, Biden won Alabama, Arkansas, Maine, Massachusetts, Minnesota, North Carolina, Oklahoma, Tennessee, Texas, and Virginia, earning a total of 458 delegates,[72] and pulling ahead of Bernie Sanders in the race.

[89][90] On May 1, Biden stated that the allegation was false and requested that the secretary of the Senate work with the National Archives and Records Administration to identify and release any relevant documents.

The Times added: With the coronavirus outbreak freezing the country’s public life, Mr. Biden has been forced to adapt to a cloistered mode of campaigning never before seen in modern American politics.

He was unable to embark on a victory tour after the Democratic primaries or hold unity rallies with onetime rivals like Senators Bernie Sanders of Vermont and Elizabeth Warren of Massachusetts.

[86] On May 13, Biden and Sanders announced that the six task forces would be co-chaired by Rep. Alexandria Ocasio-Cortez, former secretary of state John Kerry, Rep. Pramila Jayapal, former surgeon general Vivek Murthy, NILC director Marielena Hincapié, Rep. Lucille Roybal-Allard, AFA president Sara Nelson, Rep. Karen Bass, civil rights attorney Chiraag Bains, Rep. Bobby Scott, Dr. Heather Gautney, and Rep. Marcia Fudge.

[97] Six task forces were formed, each with members representing each candidate, covering climate change, criminal justice reform, the economy, education, health care, and immigration.

Chris Wallace of Fox News Sunday called Biden's acceptance speech "enormously effective" and said he "blew a big hole" in Trump's characterization of the candidate as being "mentally shot.

Debate topics included Trump's and Biden's records, the economy, the COVID-19 pandemic, race relations, and the Supreme Court nomination of Amy Coney Barrett.

[122][123] The final debate took place on Thursday, October 22, 2020, from 9:00 p.m. to 10:30 p.m. EDT, at the Curb Event Center in Belmont University in Nashville, Tennessee, with Kristen Welker of NBC moderating.

The bus, which carried former state senator Wendy Davis and several campaign staffers, was followed along the interstate by nearly 100 vehicles, including many flying Donald Trump flags.

[160] On January 6, 2021, a violent group of Trump supporters broke into the United States Capitol while Congress was counting the electoral votes in an attempt to halt or slow the proceedings.

[194] Two days later, Amy Lappos, a former congressional aide to Jim Himes, said Biden touched her in a non-sexual but inappropriate way by holding her head to rub noses with her at a political fundraiser in Greenwich in 2009.

[206] Biden received endorsements from 12 former candidates in the 2020 race, including Bernie Sanders,[207] Pete Buttigieg, Michael Bloomberg, Tulsi Gabbard, Amy Klobuchar, Kamala Harris, Cory Booker, Beto O'Rourke, Andrew Yang, and others.

On August 17, an ad from Republican Voters Against Trump aired featuring Miles Taylor, former chief of staff to former homeland security secretary Kirstjen Nielsen.

Also at the summit, he focused on economic inequality for African Americans, education access, criminal justice reform, healthcare, and voter suppression in the south.

[233] He unveiled a higher education plan in October 2019, which includes two years of guaranteed free community college or other training, and cuts to student loan obligations.

[245] While at a fundraiser on June 18, 2019, Biden said one of his greatest strengths was "bringing people together" and pointed to his relationships with senators James Eastland and Herman Talmadge, two segregationists, as examples.

[253] In May 2020, during an interview on The Breakfast Club radio show that CBS News described as "contentious", Biden remarked "If you have a problem figuring out whether you're for me or Trump, then you ain't black.

Trump enlisted surrogates within and outside his official administration, including his personal lawyer Rudy Giuliani and Attorney General William Barr, to pressure Ukraine and other foreign governments to cooperate in supporting conspiracy theories concerning American politics.

[260][261][262] Trump blocked but later released payment of a congressionally mandated $391 million military aid package to allegedly obtain quid pro quo cooperation from Volodymyr Zelenskyy, the President of Ukraine.

[268] On October 14, 2020, the New York Post, a conservative daily tabloid newspaper owned by Rupert Murdoch's News Corp, ran a story showing a screenshot of an alleged email from a top adviser to Ukrainian energy company Burisma to Biden's son Hunter, thanking him for the supposed opportunity to meet his father.

[269] The Post's source was Trump's personal lawyer Rudy Giuliani, who says he got the data from the hard drive of a laptop allegedly dropped off at a repair shop in April 2019.

"[270][271] Social media platforms swiftly responded by controlling how the article could be shared—Facebook by including a fact-checking statement and Twitter by preventing links to the story on the basis of its containing hacked material.

[275] Glenn Kessler of The Washington Post analyzed a claim, purportedly from emails of the laptop, that Joe Biden met with Burisma executive Vadym Pozharskyi at a dinner in April 2015.