The central issues of the election included the public health and economic impacts of the COVID-19 pandemic; civil unrest in reaction to the police murder of George Floyd, the Supreme Court following the death of Ruth Bader Ginsburg and confirmation of Amy Coney Barrett, and the future of the Affordable Care Act.

Key to Biden's victory were his wins in the Democratic-leaning Rust Belt states of Michigan, Pennsylvania, and Wisconsin, which Trump narrowly carried in 2016 and whose combined 46 electoral votes were enough to swing the election to either candidate.

[46][47] Governor Janet Mills allowed the bill to become law without her signature, which delayed its taking effect until after the 2020 Democratic primary in March and made Maine the first state to use RCV for a presidential general election.

[94][95] Several events related to the 2020 presidential election were altered or postponed due to the ongoing COVID-19 pandemic in the United States and its effects, such as stay-at-home orders and social distancing guidelines by local governments.

[98] The 11th Democratic debate was held on March 15 without an audience at the CNN studios in Washington, D.C.[99] Several states also postponed their primaries to a later date, including Georgia,[100] Kentucky,[101] Louisiana,[102] Ohio,[103] and Maryland.

[110][111] Government response to the impact of the pandemic from the Trump administration, coupled with the differing positions taken by congressional Democrats and Republicans regarding economic stimulus, became a major campaign issue for both parties.

[121][122][123] Later that day, the President was admitted to Walter Reed National Military Medical Center with a low grade fever, where he was reported to have received an experimental antibody treatment.

[150] On November 18, 2021, the Justice Department charged two Iranian hackers with attempting to intimidate American voters ahead of the 2020 U.S. election by sending threatening emails and spreading false information.

[212][213] On September 26, the day after Justice Ginsburg's body lay in state at the Capitol, Trump held a Rose Garden ceremony at the White House to announce and introduce his candidate, Amy Coney Barrett.

[286] Trump claimed credit for the consistent economic expansion of his presidency's first three years, with the stock market at its longest growth period in history and unemployment at a fifty-year low.

[295] As a result of the murder of George Floyd and other incidents of police brutality against African Americans, combined with the effects of the COVID-19 pandemic, a series of protests and a wider period of racial unrest erupted in mid-2020.

[324][325] In light of the attempts to contest the election results, an important question is how many votes would have had to change in particular states in order to produce a different Electoral College outcome.

[341] The task force also found "nothing untoward" while observing the handling of mail-in ballots at post offices, with Gacek being quoted as saying: "We feel that allegations of systemic wrongdoing in these elections have no solid ground.

[362] Latino voters were targeted by a major Spanish-language disinformation campaign in the final weeks of the election, with various falsehoods and conspiracy theories being pushed out by WhatsApp and viral social media posts.

Karthick Ramakrishnan, a political science professor at the University of California Riverside and founder of AAPI Data, said Asian Americans supported Biden over Trump by about a 2:1 margin.

Most pollsters underestimated support for Trump in several key battleground states, including Florida, Iowa, Ohio, Pennsylvania, Michigan, Texas, and Wisconsin.

[402][403] By the evening of November 4, the Associated Press reported that Biden had secured 264 electoral votes by winning Michigan and Wisconsin, with Pennsylvania, North Carolina, Georgia, and Nevada remaining uncalled.

[418] By November 7, several prominent Republicans had publicly denounced Trump's claims of electoral fraud, saying they were unsubstantiated, baseless or without evidence, damaging to the election process, undermining democracy and dangerous to political stability while others supported his demand of transparency.

[422] In view of these legal defeats, Trump began to employ "a public pressure campaign on state and local Republican officials to manipulate the electoral system on his behalf".

[426] At the same time, groups of Trump supporters gathered outside of election centers in Phoenix, Detroit, and Philadelphia, shouting objections to counts that showed Biden leading or gaining ground.

Prior to this recantation, Republican senator Lindsey Graham cited the claim in a letter to the Justice Department calling for an investigation, and a GoFundMe page created for the postal worker "patriot" raised $136,000.

[445] Days after Biden had been declared the winner, White House press secretary Kayleigh McEnany asserted without evidence that the Democratic Party was welcoming fraud and illegal voting.

"[447] Appearing at a press conference outside a Philadelphia landscaping business as Biden was being declared the winner, Trump's personal attorney Rudy Giuliani asserted without evidence that hundreds of thousands of ballots were questionable.

"[27] One week after the election, Republican Philadelphia city commissioner Al Schmidt said he had not seen any evidence of widespread fraud, stating, "I have seen the most fantastical things on social media, making completely ridiculous allegations that have no basis in fact at all and see them spread."

[450][451] Some senior attorneys at law firms working for Trump, notably Jones Day, expressed concerns that they were undermining the integrity of American elections by advancing arguments without evidence.

[455] This split in popular opinion remained largely stable, with a January 10, 2021, poll commissioned by ABC News showing 68% of Americans believed Biden's win was legitimate and 32% did not.

[34][506] On January 4, 2021, Democratic congressional leaders, believing Trump "engaged in solicitation of, or conspiracy to commit, a number of election crimes," requested the FBI to investigate the incident.

The change in the count was due to a number of human errors, including memory cards that did not upload properly to the state servers, and was not attributable to any fraud in the original tally.

[563] On March 31, 2021, the Republican caucus of the Arizona State Senate hired several outside firms to examine the results of the presidential and senatorial elections in Maricopa County, where Biden had won by a large margin.

[566] In July the lead firm conducting the review released a summary of major donors, indicating $5.7 million was raised from five groups associated with individuals who had cast doubt on the presidential election.