Joe Biden, the 46th president of the United States, announced in July that he would not be seeking reelection.
Following a campaign-changing performance in June's presidential debate, Biden's age and health — which have long been his biggest political weakness, dating back to his third run for the presidency starting in 2019 — have been under the microscope.
He was growing increasingly isolated from many corners of his Democratic Party as he faced deepening questions about whether he should continue his reelection campaign.
Biden defeated Donald Trump in the 2020 election and became the oldest commander in chief in US history when he was inaugurated a few months later at the age of 78.
For more than 35 years, Biden represented Delaware in the US Senate. He resigned in 2009 to become vice president under Barack Obama.
He ran for president in 1988 and 2008 before breaking through in 2020.