Donald Trump is a braggart and a liar. Donald Trump attempted to stage a coup. I think both those statements are true. But it is also true that, as president, Trump was responsible for historic shifts in US foreign and domestic policy that Joe Biden has built upon. Those shifts are likely to endure — even if Trump is sent to prison.
What makes a presidency truly historic? Essentially, it requires a radical break with the past — whose consequences and premises are then accepted and absorbed by your political opponents. Franklin Roosevelt did it with the New Deal. Lyndon Johnson did it with the Civil Rights Act. Ronald Reagan did it with the deregulating, tax-cutting policies, now commonly referred to as neoliberalism.