Joe Biden enters the presidential race, testing whether his time has come — or come and gone

Former U.S. Vice President Joe Biden leaves a rally in Dorchester, Mass., organized by the United Food and Commercial Workers International Union to support Stop and Shop employees on strike throughout the region on April 18, 2019.

Former Vice President Joe Biden visits a conference of the International Brotherhood of Electrical Workers in Washington on April 05, 2019.

Former Vice President Joe Biden speaks to supporters of Sen. Claire McCaskill at a “get out the vote” rally on Oct. 31, 2018, in Bridgeton, Mo. McCaskill later lost a tight race to Republican challenger Josh Hawley.

Children join former Vice President Joe Biden on stage as he speaks at an International Brotherhood of Electrical Workers conference in Washington on April 5, 2019.

Former Vice President Joe Biden attends a rally in support of Democratic congressional candidate Conor Lamb, center, on March 6, 2018, in Pittsburgh. Lamb won a tight race for the vacated seat of Rep. Tim Murphy against Rick Saccone.

Members of the International Assn. of Fire Fighters listen as former U.S. Vice President Joe Biden speaks at the group’s legislative conference on March 12, 2019, in Washington. The conference addressed issues including firefighters’ mental health, funding the 9/11 Victims Compensation Fund and collective bargaining.

Former U.S. Vice President Joe Biden speaks at the International Assn. of Fire Fighters legislative conference in Washington on March 12, 2019.