Former Vice President Joe Biden launches 2020 presidential campaign

WASHINGTON - Joe Biden has officially launched his presidential campaign for 2020, making him the 20th Democratic candidate to join the race.

The former vice president announced his third run for president in a video released online Thursday.

Biden joins a diverse set of contenders, including six women, five people of color, and one member of the LGBTQ community. At 76 years old, he is the second-oldest, but he has the most political experience of any candidate.

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 help him enter the race as a front-runner, though he faces questions about his age, and it's unclear if he will appeal to the more liberal voters who tend to have outsized sway in Democratic primary contests.

A handful of lesser-known Democrats, including Montana Gov. Steve Bullock, could join the race in the coming weeks or months, but Biden's decision is considered the final major piece as voters, donors and elected officials alike begin to pick their favorites.

"Come on in, the water is warm, Joe," California Sen. Kamala Harris, another 2020 contender, laughed on Tuesday as she campaigned in New Hampshire. "I adore Joe Biden and I think he has to make whatever decision is best for him."

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

The largest firefighters union is preparing to formally endorse Biden, with group leaders saying they will be "investing" heavily in the former vice president's anticipated bid.

The board of the International Association of Fire Fighters will meet this week to vote on the endorsement. They plan to announce it publicly early next week.

IAFF represents 316,000 full-time firefighters across the U.S. Harold A. Schaitberger, the union's general president, said the group will help Biden raise money. It will also launch an outside group that is expected to be able to raise and spend unlimited sums supporting his candidacy.

"I always remind everyone that we are everywhere there is a blinking light or traffic light," Schaitberger said. "We have infrastructure and capability, whether it's in the neighborhoods, or whether it's working to develop caucus attendees in Iowa. Our union is very strongly resourced and we will be investing."

Biden spoke at an IAFF gathering in Washington last month. At the time Schaitberger said the union would be "all in" for Biden if he runs. He also acknowledged that many rank-and-file members supported President Donald Trump in 2016.

Biden, Schaitberger argued, is better positioned than other Democrats to win in the Midwest, which flocked to Trump in 2016.

The Associated Press contributed to this report.