Former Vice President Joe BidenThursday, bringing to a halt months of speculation. Although he is widely known for his tight-knit relationship with President Obama during Mr. Obama's eight years in the White House, Biden served in Congress for nearly 35 years and ran two unsuccessful campaigns for president. His long career in public life has also been shaped by two family tragedies.
Here's everything you need to know about the 76-year-old lawmaker from Delaware and latest 2020 Democratic contender:
Biden was born in Scranton, a city in northeastern Pennsylvania, in late 1942, when the U.S. was fighting the Axis powers in World War II. In the 1950s, his family moved to Delaware, where he attended a private Catholic academy and eventually, the University of Delaware for his bachelor's degree in political science and history. After earning his law degree from Syracuse University in 1968, Biden worked for several law firms before being elected to a seat in the New Castle County Council.
After only a few years in that post, Biden decided to launch an underdog campaign for one of Delaware's Senate seats in 1972. Despite having little experience, he beat Sen. Caleb Boggs, a 12-year incumbent, in the general election.
His surprising victory, however, was overshadowed by tragedy. Biden lost his first wife, Neilla Hunter, and one-year-old daughter, Naomi, to a car accident days before Christmas in 1972. His sons, Beau and Hunter, were badly injured but survived. The grief reportedly prompted Biden to reconsider joining the Senate, but he decided to assume the position. At age 30, he was sworn in as one of the youngest U.S. senators in 1973 at the Wilmington Medical Center, where Beau was still recovering from his injuries.
During his long tenure in Congress, Biden solidified himself as one of the most influential members of the Senate, leading two of its most powerful panels, the Judiciary and Foreign Affairs Committees, during different terms. He was considered a centrist Democrat who was willing to hash out bipartisan deals with Republicans.
During his time in Congress, Biden remarried and commuted to Washington, D.C. from his home in Delaware via Amtrak — so he could see his sons every night after they lost their mother and sister.
Biden also sought the Democratic presidential nomination in 1988 and 2008, dropping out during the primary in both. The one in 1988 was derailed by a plagiarism scandal while in 2008, he failed to gain much traction in the primary and made several gaffes on the campaign trail. After Biden dropped out of the 2008 race, Mr. Obama, at the time the Democratic Party's nominee, picked the Delaware senator to be his running mate.
After Mr. Obama's historic election, Biden resigned from the Senate to be sworn in as America's 47th vice president in 2009. Over the following eight years, Biden was a loyal advocate for Mr. Obama's policies and the two developed a strong friendship.
Along with being a valuable White House negotiator with congressional Republicans after the GOP took control of the House in 2011, he was tasked with overseeing administration efforts on infrastructure spending, sexual violence and cancer research — an area that became very personal for him.
In May 2015, his eldest son, Beau, died at age 46 after a battle with brain cancer. Beau's death was one of the reasons his father opted not to run for president in 2016, a decision he has repeatedly said he regrets.
With his announcement that he is seeking the Democratic nod for president in 2020, Biden is hoping to become the oldest president at the time of inauguration as well as the only Catholic president since John F. Kennedy.
Although he will be backed by major Democratic donors and many of the Democratic Party's top leadership, Biden will surely face some criticism from progressive Democrats for some of the positions and actions he took during his long career in the Senate.
In the 1970s, Biden opposed busing to desegregate public schools. As chairman of the Senate Judiciary Committee, he oversaw the contentious Anita Hill hearings during the confirmation process for then-Supreme Court nominee Clarence Thomas in 1991. Progressives have denounced his handling of the hearing, alleging he did not do enough to empower Hill's testimony. Biden also helped spearhead efforts to pass the Violent Crime Control and Law Enforcement Act of 1994 that many believe fueled a period of mass incarceration that disproportionately affected African-Americans and other minority groups.
Separately, Biden has come under scrutiny in recent weeks by several women who said he touched them inappropriately at events over the years. In a video earlier this month, he pledged to be more respectful of personal spaces, but stopped short of offering a full apology.
What Trump says
Biden was sharply critical of then-candidate Donald Trump on the 2016 campaign trail, where he stumped for Hillary Clinton. During Mr. Trump's time in the White House, the former vice president has consistently spoken out against the administration's policies and rhetoric. Last year, he told a crowd he would've "beat the hell out" of Mr. Trump because of his remarks about women if the two had been in high school together. The president responded by accusing Biden of trying to be a "tough guy."
Since reports have surfaced about Biden joining the 2020 race to challenge him, the president has called the former vice president a "sleepy" and non-threatening potential general election opponent
"I don't see Joe Biden as a threat," Mr. Trump told reporters earlier this month.