Speaking from the Oval Office as he prepares to hand over power Monday to President-elect Donald Trump, Biden seized what is likely to be his final opportunity to address the country before he departs the White House to spotlight the accumulation of power and wealth in the U.S. among just a small few.

“Today, an oligarchy is taking shape in America of extreme wealth, power and influence that literally threatens our entire democracy, our basic rights and freedoms, and a fair shot for everyone to get ahead,” Biden said, drawing attention to “a dangerous concentration of power in the hands of a few ultra-wealthy people and the dangerous consequences if their abuse of power is left unchecked.”

Invoking President Dwight Eisenhower’s warnings about the rise of a military-industrial complex when he left office in 1961, Biden added, “I’m equally concerned about the potential rise of a tech-industrial complex that could pose real dangers to our country as well.”

Biden used his 15-minute address to offer a model for a peaceful transfer of power and — without mentioning Trump by name — raise concerns about his successor.

It marked a striking admonition by Biden, who is departing the national stage after more than 50 years in public life, as he has struggled to define his legacy and to steel the country against the return of Trump to the Oval Office. This time, the president, who has repeatedly called Trump a threat to the nation’s system of governance, went even further, warning Americans to be on guard for their freedoms and their institutions during a turbulent era of rapid technological and economic change.

Biden sounded the alarm about oligarchy as some of the world’s richest individuals and titans of its technology industry have flocked to Trump’s side in recent months, particularly after his November victory. Billionaire Elon Musk spent more than $100 million helping Trump get elected, and executives like Meta’s Mark Zuckerberg and Amazon’s Jeff Bezos have donated to Trump’s inaugural committee and made pilgrimages to Trump’s private club in Florida for audiences with the president-elect as they seek to ingratiate themselves with his administration and shape its policies.

Biden’s speech in the Oval Office is the latest in a series of remarks on domestic policy and foreign relations he has delivered that are intended to cement his legacy and reshape Americans’ grim views on his term. Earlier in the day, he heralded a long awaited ceasefire agreement between Israel and Hamas, which could end more than a year of bloodshed in the Middle East.

“It’ll take time to feel the full impact of what we’ve done together but the seeds are planted and they’ll grow and they’ll bloom for decades to come,” Biden said. It was a tacit acknowledgement that many Americans say they have yet to feel the impact of his trillions of dollars spent on domestic initiatives.

At the same time that Biden was criticizing social media companies for retreating from fact-checking on their platforms, Trump’s incoming communications director and press secretary were sharing posts on X that falsely claimed the president had delivered a prerecorded speech. Biden has blamed his poor standing with the public on misinformation on social media and the challenges he has faced reaching voters in the disaggregated modern media ecosystem.

Biden offered his own set of solutions for the problems that he laid out: change the tax code to ensure billionaires “pay their fair share,” eliminate the flow of hidden sources of money into political campaigns, establish 18-year term limits for members of the Supreme Court and ban members of Congress from trading stocks. His policy prescriptions come as his political capital is at its nadir as Biden prepares to exit the national stage, and after he has done little to advance those causes during his four years in power at the White House.

Federal Reserve data shows the wealthiest 0.1% of the country combined holds more than five times the wealth of the bottom 50% combined.

Biden isn’t leaving the White House in the way that he hoped. He tried to run for reelection, brushing aside voters’ concerns that he would be 86 years old at the end of a second term. After stumbling in a debate with Trump, Biden dropped out of the race under pressure from his own party, and Vice President Kamala Harris became the Democratic nominee.

The speech Wednesday night capped not just Biden’s presidency but his five decades in politics. He was once the country’s youngest senator at 30 years old after being elected to represent his home state of Delaware in 1972.

Biden pursued the presidency in 1988 and 2008 before becoming Barack Obama’s vice president. After serving two terms, Biden was considered to be retired from politics. But he returned to center stage as the unlikely Democratic nominee in 2020, successfully ousting Trump from the White House.

As he highlighted his own commitment to ensuring a peaceful transition of power, including holding briefings with Trump’s team and coordinating with the incoming administration on the Middle East negotiations, Biden also called for a constitutional amendment to end immunity for sitting presidents. That came in response to a Supreme Court ruling last year that granted Trump sweeping protections from criminal liability over his role in trying to overturn his 2020 defeat to Biden.

Biden spoke from the Resolute desk, photos of his family visible behind him in the Oval Office. First lady Jill Biden, his son Hunter, some of his grandchildren, Harris and her husband, Doug Emhoff, sat watching.

As Biden spoke about Harris, saying she’d become like family, the first lady reached over and grabbed her hand.