Joseph R. Biden Jr. forcefully defended Social Security in a speech to disability advocates in Chicago on Tuesday, condemning the Trump administration for “taking a hatchet” to the Social Security Administration.

In his first expansive public comments since leaving the White House, Biden said that President Trump had taken aim at Social Security, doing “damage and destruction” to a program that millions of Americans depend on.

“Social Security deserves to be protected for the good of the nation as a whole,” Biden said, adding that Trump officials are applying a Silicon Valley mantra of “move fast and break things” to the government. “Well, they’re certainly breaking things. They’re shooting first and aiming later.”

Trump has promised not to cut Social Security benefits for the 73 million Americans enrolled, but offices around the country have been flooded with calls and questions from Americans who are worried that changes to their benefits and to their local Social Security offices may be imminent.

At local offices, many staff members have taken buyouts or early retirements promoted by the Trump administration’s cost-cutting efforts, leading to longer phone waits and lines. The Social Security Administration has said it wants to shed thousands of jobs at its headquarters.

Biden said that during his own administration, the Social Security Administration cut wait times, improved antifraud measures and made the appeals system for benefits more uniform. “It all became more efficient and more effective,” he said, drawing applause from the audience, a group of hundreds of lawyers and other professionals who advocate on behalf of people with disabilities.

Biden, 82, has kept a relatively low profile since he left the White House in January. He was seen attending the opening night of “Othello” on Broadway. He has popped into a diner in Delaware and an Italian restaurant in Georgetown, and regularly ridden the Amtrak between his home in Delaware and a post-presidential office in Washington.

Over the weekend, Biden attended a Seder with Gov. Matt Meyer of Delaware, a fellow Democrat who wrote on social media that they had “prayed for Gov. Josh Shapiro and his family” after the arson attack on the Pennsylvania governor’s home.

Biden has been in touch with a number of former top advisers and former senior administration officials, including Bruce Reed, Steve Ricchetti, Jake Sullivan, Jeff Zients and Antony J. Blinken, according to two people close to him.

The same top aides are surrounding him in his post-presidential life, including Annie Tomasini, who was a deputy chief of staff in the White House, and Anthony Bernal, who was a senior adviser for Jill Biden.

Behind the scenes, Biden has been in touch with some lawmakers and the new head of the Democratic National Committee, Ken Martin. Martin met with Biden at the former president’s offices in Washington after Martin won the chairmanship, and the former president offered to be supportive, two people briefed on the meeting said.

Biden has begun work on a memoir about his time in office, after signing on with the Creative Arts Agency, which represented him between 2017 and 2020. He declined to participate in the many books by journalists about the 2024 campaign. The Chicago speech marks the beginning of what could be a stretch on the speaker circuit for Biden.

New York Times News Service