WASHINGTON (AP) — President Joe Biden has used his farewell address to the nation to warn of an “oligarchy” of the ultra-wealthy taking root in the country and of a “tech-industrial complex” that is infringing on Americans’ rights and the future of democracy. Speaking Wednesday from the Oval Office as he prepares to hand over power to President-elect Donald Trump, Biden spotlighted the accumulation of power and wealth in the U.S. among just a small few. The president warned Americans to be on guard for their freedoms and their institutions during a turbulent era of rapid technological and economic change. Biden also called for a constitutional amendment to end immunity for sitting presidents.