WASHINGTON — Former Vice President Joe Biden's bid for the White House has been rumored for months.  

On Thursday morning, Biden made the announcement he is running for president. 

He made his announcement in a video posted on social media, declaring, "We are in the battle for the soul of this nation."

"If we give Donald Trump eight years in the White House, he will forever and fundamentally alter the character of this nation," Biden said. "Who we are. And I cannot stand by and watch that happen."

Thursday’s announcement marks the unofficial end of the chaotic early phase of the 2020 presidential season. The field now features at least 20 Democrats jockeying for the chance to take on President Donald Trump next year. Several lesser-known candidates may still join the race.

The move sets up the 76-year-old lifelong politician as a front-runner in the crowded Democratic contest as the party fights to determine who's best positioned to defeat Trump next year.

Biden, who spent the past five decades in Washington but never lost touch with his working-class background, is scheduled to face union workers in Pittsburgh on Monday as part of the rollout tour, the person said, speaking on the condition of anonymity to disclose private conversations.

His decision largely settles the crowded and diverse Democratic presidential field at 20 candidates, including six women, five people of color and one member of the LGBTQ community. Biden would be the most experienced politician in the race, and the second-oldest, after 77-year-old Bernie Sanders.

Biden, who has run for president twice before with little success, will look to organized labor for support early on.

One of the most recognizable names in politics, Biden served for two terms as Barack Obama's vice president after nearly four decades as a senator from Delaware. 

His high-profile, working-class background and connection to the Obama years would help him enter the race as a front-runner, though he faces questions about his age and whether his more moderate record fits with a party that has become more liberal.

Trump went to Twitter to send Biden a message.

The 2020 Democratic National Convention is still more than a year away, scheduled for July 13 to 16, 2020, in Milwaukee.