WASHINGTON — After months of deliberation, former Vice President Joe Biden on Thursday announced his decision to run for president for a third time, answering one of the biggest outstanding questions about the makeup of the 2020 race.

The announcement came in a campaign video released Thursday morning.

Biden, 76, enters the crowded Democratic primary field of 20 candidates as the presumptive front-runner sitting atop the most recent polls. But his more than four-decades-long career is set to undergo an unprecedented level of scrutiny as he seeks to win the Democratic nomination to take on President Donald Trump in a general election.

In recent weeks, Biden indicated he was close to mounting a 2020 campaign after gaining approval from his family to run for president for a third time. But he also acknowledged there were a number of other hurdles he still needed to work through, including fundraising, digital strategy, assembling a diverse campaign team and ensuring there is an appeal for a Biden run.

Biden’s announcement comes in the wake of allegations he has made women feel uncomfortable in their encounters. The former vice president has maintained he does not believe he has acted inappropriately in his interactions with voters but said he’s willing to listen to women’s experiences and will be more “mindful about respecting personal space in the future.”

This will mark Biden’s third attempt for the White House after two failed bids in 1988 and 2008.