Three groups representing older Americans on Wednesday endorsed Democrat Joe Biden for a second term as president as his campaign works to expand existing support among seniors, a bloc that could help offset softer backing among other voters.

The National Committee to Preserve Social Security & Medicare (NCPSSM), which defied a 38-year tradition of avoiding endorsements to back Biden in 2020, Social Security Works PAC and the bipartisan National United Committee to Protect Pensions all said they would back Biden in 2024.

The endorsements, which had not been previously reported, follow the January endorsement of Biden by the 4.4-million member Alliance for Retired Americans.

Max Richtman, president of the NCPSSM, said Biden had worked to protect seniors' earned benefits and the group did not trust Donald Trump to safeguard Social Security and Medicare.

Biden's campaign manager, Julie Chavez Rodriguez, said the groups represented tens of millions of seniors, who would organize, mobilize, and activate their peers ahead of the U.S. presidential election this November.

"With today’s endorsements, we will be stronger and more prepared than ever to mobilize seniors across the country, to remind voters of how dangerous Trump and his policies are and to make him a loser again this November.”

The campaign on Tuesday launched Seniors for Biden-Harris, a grassroots program to energize voters 65 and up with more than a dozen events from bingo nights to pickleball tournaments to appearances by senior administration officials.

Older Americans could play a key role in the election, given that they vote at higher levels than any other group and account for nearly 10 million voters in key election battleground states, including Wisconsin, Michigan, Pennsylvania, North Carolina, Georgia, Arizona and Nevada.

Seniors generally vote majority Republican, but their growing support for Biden, 81, the oldest person to serve as president, could be good news for the Democrat, whose approval rating fell to its lowest level in almost two years in May.

Americans 65 and older numbered nearly 56 million in the 2020 census, or just under 17% of the U.S. population. Trump won voters of that age by 7 percentage points in 2016, but Biden narrowed the gap to 5 points in 2020, and now has a narrow lead, according to an April NBC News poll.

(Reporting by Andrea Shalal. Editing by Gerry Doyle and Christina Fincher)