On this day four years ago, Barack Obama welcomed president-elect Donald Trump to the White House.
It was an awkward situation to say the least. The two men were bitter political enemies, with a long history of attacking and mocking each other.
Trump had spent years promoting the "birther" conspiracy theory, which claimed Obama was not actually a US citizen and therefore ineligible to be president.
Obama had famously roasted Trump at the 2011 White House correspondents' dinner, and spent most of 2016 warning he was unfit to be president.
Needless to say, there was a lot of bad blood between them.
Nevertheless, Trump had won the election two days earlier, and facilitating a smooth transition was part of Obama's job. So he invited his successor to the White House.
After meeting behind closed doors, the pair briefly appeared for an excruciating photo op in the Oval Office, during which they pretended not to hate each other's guts.
Both men offered warm words.
"I just had the opportunity to have an excellent conversation with president-elect Trump," Obama told the assembled reporters.
"It was wide-ranging. We talked about some of the organisational issues in setting up the White House. We talked about foreign policy. We talked about domestic policy. And as I said last night, my number one priority in the coming two months is to try to facilitate a transition that ensures our president-elect is successful.
"And I have been very encouraged by the, I think, interest in president-elect Trump's wanting to work with my team around many of the issues that this great country faces. And I believe that it is important for all of us, regardless of party and regardless of political preferences, to now come together, work together, to deal with the many challenges that we face.
"Most of all, I want to emphasise to you, president-elect, that we now are going to want to do everything we can to help you succeed, because if you succeed, then the country succeeds."
He then yielded the floor to the man for whom he'd later yield the White House.
"Well, thank you very much, President Obama," Trump said.
"This was a meeting that was going to last for maybe 10 or 15 minutes, and we were just going to get to know each other. We had never met each other. I have great respect.
"The meeting lasted for almost an hour and a half. And it could have – as far as I'm concerned, it could have gone on for a lot longer.
"We really, we discussed a lot of different situations, some wonderful, and some difficulties. I very much look forward to dealing with the president in the future, including counsel.
"He explained some of the difficulties, some of the high-flying assets and some of the really great things that have been achieved.
"So, president, it was a great honour being with you, and I look forward to being with you many, many more times in the future."
Obviously, this friendly attitude didn't last. This year we have seen the pair's relationship reach new levels of acrimony, with Trump baselessly accusing Obama of illegally "spying" on his 2016 campaign, Obama labelling his successor a threat to American democracy, and each man mocking the other relentlessly at their respective rallies in the closing weeks of the campaign.
But in that crucial moment four years ago, Obama and Trump tried to make it work, because the peaceful transition of power was more important than either man's ego.
That principle was also reflected in a speech the day before the White House meeting.
Addressing Hillary Clinton's defeat to Trump for the first time, Mr Obama (and then-vice president Joe Biden) fronted the cameras together and spoke about the importance of a smooth transition.
"Yesterday, before votes were tallied, I shot a video that some of you may have seen in which I said to the American people, regardless of which side you were on in the election, regardless of whether your candidate won or lost, the sun would come up in the morning," Obama said.
"And that is one bit of prognosticating that actually came true. The sun is up. And I know everybody had a long night. I did as well.
"I had a chance to talk to president-elect Trump last night, at about 3:30 in the morning, I think it was, to congratulate him on winning the election. And I had a chance to invite him to come to the White House tomorrow to talk about making sure that there is a successful transition between our presidencies.
"Now, it is no secret that the president-elect and I have some pretty significant differences. But remember, eight years ago President Bush and I had some pretty significant differences. But President Bush's team could not have been more professional or more gracious in making sure we had a smooth transition so that we could hit the ground running.
"And one thing you realise quickly in this job is that the presidency and the vice presidency are bigger than any of us. So I have instructed my team to follow the example that President Bush's team set eight years ago, and work as hard as we can to make sure that this is a successful transition for the president-elect.
"Because we are now all rooting for his success in uniting and leading the country. The peaceful transition of power is one of the hallmarks of our democracy. And over the next few months, we are going to show that to the world."
Obama spent much of the speech directly addressing Democrats who were horrified by Trump's victory.
"A lot of our fellow Americans are exalted today, a lot of Americans less so, but that's the nature of campaigns, that's the nature of democracy. It is hard and sometimes contentious and noisy and it's not always inspiring," he said.
"We try really hard to persuade people that we're right, and then people vote. And then if we lose, we learn from our mistakes, we do some reflection, we lick our wounds, we brush ourselves off, we get back in the arena, we go at it. We try even harder the next time.
"The point, though, is that we all go forward with a presumption of good faith in our fellow citizens, because that presumption of good faith is essential to a vibrant and functioning democracy.
"That's how this country has moved forward for 240 years. It's how we've pushed boundaries and promoted freedom around the world. That's how we've expanded the rights of our founding to reach all of our citizens. It's how we have come this far."
Fast forward four years, and the situation could not be more different.
Biden has won the election, and appears to be on track to win the same number of electoral votes (306) as Trump did in 2016. He's also won the popular vote by a margin of more than four million.
President Trump is refusing to concede defeat, and has shown no sign he intends to facilitate a smooth transition for the president-elect.
"We all know why Joe Biden is rushing to falsely pose as the winner, and why his media allies are trying so hard to help him. They don't want the truth to be exposed. The simple fact is this election is far from over," he said in a statement after Biden passed the 270-electoral vote threshold he needed to win.
"The American people are entitled to an honest election. That means counting all legal ballots, and not counting any illegal ballots. This is the only way to ensure the public has full confidence in our election.
"It remains shocking that the Biden campaign refuses to agree with this basic principle and wants ballots counted even if they are fraudulent, manufactured, or cast by ineligible or deceased voters. Only a party engaged in wrongdoing would unlawfully keep observers out of the count room, and then fight in court to block their access.
"So what is Biden hiding? I will not rest until the American people have the honest vote count they deserve and that Democracy demands."
Several of the assertions in that statement are false. The part about election observers, in particular, is categorically untrue.
Trump and his campaign have yet to provide any evidence to support their claims of widespread fraud in the election.
In any case, it's clear Biden won't be receiving an invitation to the White House any time soo