CHICAGO — Former President Joe Biden warned on Tuesday that President Donald Trump has “taken a hatchet” to Social Security, weighing in on a critical issue for millions of Americans as the 82-year-old Democrat briefly returned to the national stage.

Biden, who has largely avoided speaking publicly since leaving the White House in January, gave an evening speech at the national conference of Advocates, Counselors and Representatives for the Disabled in Chicago. The former president was speaking as Democrats across the nation offered similar warnings for what they described as a Social Security Day of Action.

“In fewer than 100 days, this new administration has done so much damage and so much destruction. It’s kind of breathtaking,” Biden charged during a speech that spanned just under a half-hour. “They’ve taken a hatchet to the Social Security Administration.”

It was no coincidence that Tuesday’s appearance, which marked Biden’s first major event since leaving office, was focused on Social Security. Democrats have increasingly focused on Trump’s turbulent leadership over the popular government agency that provides benefits to more than 70 million Americans.

Both parties expect Social Security to emerge as a key issue in next year’s midterm elections.

Speaking before a crowd of roughly 200 people, Biden largely stuck to his prepared remarks but also rambled at times as he told stories about growing up with working-class people.

He referred to the Republican president only as “this guy.” Trump, by contrast, continues to blame Biden for many of the nation’s problems and often attacks his predecessor by name.

Conservatives immediately seized upon a Biden reference to the country’s political divisions as an attack on Trump supporters.

“We can’t go on like this as a divided nation, as divided as we are,” Biden said. “As I said, I’ve been doing this a long time. It’s never been this divided. Granted, it’s roughly 30%, but it’s a 30% that has no heart.”

Earlier in the day, White House press secretary Karoline Leavitt took a shot at the former president’s age and fitness when asked about Biden’s appearance.

“I’m shocked that he is speaking at nighttime,” Leavitt said during Tuesday’s White House press briefing. “I thought his bedtime was much earlier.”

She said that Trump, who is 78 years old, would sign a presidential memorandum Tuesday afternoon “aimed at stopping illegal aliens, and other ineligible people, from obtaining” Social Security benefits. The memorandum will expand the Social Security Administration’s fraud prosecutor program to at least 50 U.S. attorney offices, and establish Medicare and Medicaid fraud prosecution programs in 15 U.S. attorney offices, Leavitt said.

The Social Security Administration pushed back against Biden’s remarks using its official X account.

“Former President Joe Biden is lying to Americans,” the agency wrote.

The Republican president almost immediately began slashing the government workforce upon his return to the White House, including thousands of employees at the Social Security Administration. Along with a planned layoff of 7,000 workers and contentious plans to impose tighter identity-proofing measures for recipients, the SSA has been sued over a decision to allow Trump adviser Elon Musk’s Department of Government Efficiency to access individuals’ Social Security numbers and other personally identifiable information.

At the same time, Social Security recipients have complained about long call wait times as the agency’s “my Social Security” benefits portal has seen an increase in outages. Individuals who receive Supplemental Security Income, including disabled seniors and low-income adults and children, also reported receiving a notice that said they were “not receiving benefits.”

The agency said the notice was a mistake. And the White House has vowed that it would not cut Social Security benefits, saying any changes are intended to reduce waste and fraud.