How did Joe Biden secure the presidency?

After five drawn out days, Joe Biden has won the White House

President-elect Joe Biden pumps his fist on stage with his vice-president elect Kamala Harris. AP Photo

Joe Biden was declared the next US president on Saturday after a marathon election was finally sealed by a tidal wave of mail-in ballots from Pennsylvania that favoured the Democrat.

In an election unlike any other, Americans and international observers spent five days keenly watching as four battleground states released voter returns, often a few thousand ballots at a time.

After days of anticipation, Mr Biden swung head in Pennsylvania by nearly 35,000 ballots on Saturday and the Associated Press along with several US media outlets declared the lead was too wide for Donald Trump to make up. Joe Biden was declared the 46th president of the United States.

Shortly after, the state of Nevada was also called for Mr Biden, giving him 290 electoral votes and further securing his grasp on a hotly contested presidency.

Mr Biden’s heavy focus on his home state of Pennsylvania during the final days of campaigning paid off for him. He won the large majority of mail-in ballots that came from the state.

Pennsylvania, like the other swing states of Nevada, Georgia and Arizona, was not allowed to pre-process their mail-in ballots, which caused a large backlog of early votes that elections officials worked tirelessly to count over five days.

As nail-biting returns were released by the states, a few trends emerged that helped to push Mr Biden towards the presidency. The Democrat was largely the favourite among voters who mailed in their ballots, while Mr Trump faired best with Americans who voted in person on November 3. This explains how Mr Trump pulled ahead in the early hours of the election, but lost his advantage as more mail-in ballots were tabulated.

The Republican candidate repeatedly called into question the legitimacy of postal ballots and told his supporters not to vote by mail, despite the voting method being entirely secure and fair. Mr Trump’s insistence that the US Postal Service was not reliable is partly why his lead in the race dwindled in the days following the election.

Mr Trump made several unfounded claims as his lead in the election slipped away, and Republicans in swing states have issued a number of lawsuits to contest the counting of mail-in and provisional ballots. Many of the lawsuits have already been thrown out for a lack of evidence.

By Friday, it was all but official that Mr Biden had won the presidency. The shift many Biden supporters were waiting for came when the states of Georgia and Pennsylvania flipped blue as Mr Biden pulled ahead of Mr Trump.

Georgia has not voted for a Democratic president since 1992. Mr Biden also leads in the traditionally Republican state of Arizona.

Mr Biden will inherit a White House in crisis as the US hit record-high daily Covid-19 infections on the day of his win, and the US economy is shaking under the impact of the pandemic. The election occurred during a period of distress in America, which may explain some of the significant shifts in voting patterns that were seen during this election.

From a record 147 million ballots that were cast, the popular vote went to Mr Biden by a notable margin, with the president-elect securing 4.5 million more votes than Mr Trump nationally. Due to the US electoral college model, the popular vote is not a determining factor in election outcomes.

Mr Biden won the presidency exactly 48 years to the day after he was first elected to the Senate.