Pres. Donald Trump moves swiftly to implement his new agenda after inauguration

As President Joe Biden prepared to pass the baton to President-elect Donald Trump, he's followed the tradition of leaving his successor a note.

While Biden confirmed that he wrote Trump a letter, he did not say what his message was.

President Ronald Reagan started the ritual of leaving his successor a letter in 1989. Every president since has taken part in the tradition. But since Reagan's letter to Bush, each handover has been from a Democrat to a Republican or vice versa.

The peaceful transition of power is a hallmark of American democracy.

It's currently on display as Biden hosts Trump at the White House before they attend the inauguration together.

But four years ago, Trump denied Biden such a welcome. Instead, he bitterly left Washington hours before the inauguration while still refusing to concede he lost the 2020 election.

"The only president ever to avoid an inauguration is the guy that's about to be inaugurated," Biden had said when he confirmed he would be in attendance for Monday's events.

Former Vice President Mike Pence announced his plans to attend the inauguration.

"Today, I will attend the Inauguration of President Donald Trump and Vice President J.D. Vance at the U. S. Capitol," Pence wrote on X. "This is a day when every American does well to celebrate our democracy and the peaceful transfer of power under the Constitution of the United States."

Pence was seen arriving at the U.S. Capitol at around 9:30 a.m.

Trump and Vance have had a contentious relationship and did not interact publicly for four years after Pence broke with Trump by refusing to reject the 2020 election results.

- ABC News' Oren Oppenheim

As Trump exited his limousine, Biden said to him: "Welcome home."

Trump walked up the steps with Melania Trump and they shook hands with the Bidens.