Former President Joe Biden described the current period as “dark days,” urging Americans to remain hopeful and engaged despite what he perceives as significant challenges to free speech and executive power being tested by President Donald Trump.

“Since its inception, America has been a beacon of the most powerful idea in governance throughout world history,” Biden remarked. “This idea surpasses any military might and is more formidable than any dictator.”

At 82, Biden made his first public appearance since completing radiation treatment for an aggressive prostate cancer. He addressed a crowd in Boston on Sunday night, following his receipt of the Lifetime Achievement Award from the Edward M. Kennedy Institute.

He emphasized the importance of a presidency with restricted power, a functioning Congress, and an independent judiciary as the foundation of America. With the federal government nearing its second-longest shutdown, Biden criticized Trump for leveraging funding lapses to assert greater control over governmental operations.

“Friends, there’s no sugarcoating this. These are indeed dark days,” Biden stated, expressing optimism that the nation will “rediscover our true direction” and “emerge stronger, wiser, more resilient, and more just, as long as we maintain our faith.”

Biden highlighted examples of resistance against the current administration, including federal employees resigning in protest and universities and comedians who have been targeted by Trump.

“The late night hosts continue to shine a light on free speech knowing their careers are on the line,” he said.

Biden also shouted out elected Republican officials who vote or openly go against the Trump administration.

“America is not a fairy tale,” he said. “For 250 years, it’s been a constant push and pull, an existential struggle between peril and possibility.”

He finished the speech by telling people to “get back up.”

The Democrat left office in January after serving one term in the White House. Biden dropped his bid for reelection after facing pressure following a disastrous debate against Trump and concerns about his age, health and mental fitness. Vice President Kamala Harris launched her bid right after, but lost to Trump last November.

In May, Biden’s post presidential office announced that he had been diagnosed with prostate cancer and that it had spread to his bones.

Prostate cancers are graded for aggressiveness using what is known as a Gleason score. The scores range from 6 to 10, with 8, 9 and 10 prostate cancers behaving more aggressively. Biden’s office said his score was 9.