Behind the smiles, as Joe Biden bids farewell to world leaders at the UN General Assembly this week, will be one goal -- shoring up his legacy against a possible White House comeback by Donald Trump.
Countries around the world are nervously watching November's US presidential election amid fears that a Trump victory over Kamala Harris would bring back his hardline, isolationist foreign policy.
And as Biden makes his final appearance at the UN General Assembly in New York, after dropping out of the race in July and endorsing his vice president as the Democratic nominee, the 81-year-old is not taking any chances.
Viewing his presidency as a return from the brink after Republican Trump's four years in the Oval Office, Biden will be trying to make sure his achievements are, in the words of one advisor, "irreversible."
From his keynote address to the United Nations and a major climate speech on Tuesday, to talks on the wars in Gaza, Ukraine and Sudan, Biden will be trying to lay the ground for US alliances and leadership that could outlast Trump.
"When President Biden came to office nearly four years ago he pledged to restore American leadership on the world stage," White House Press Secretary Karine Jean-Pierre told reporters traveling with him to New York.
Biden would now use his UN address to outline his "vision" for how that should continue -- and to "reaffirm how this approach has produced results for the American people and for the world," she added.
His UN swan song is part of a wider attempt to burnish his legacy at home and abroad after a one-term presidency cut short when a disastrous debate against Trump fueled concerns about his age.
In an emotional moment Sunday, on the eve of the assembly, former president Bill Clinton presented Biden with the "Clinton Global Citizen Award" at a surprise ceremony in New York.
- 'Irreversible momentum' -
Biden held a cabinet meeting last week to urge a "sprint to the finish" to promote his policies -- and to give any reflected glory to Harris in an agonizingly close election.
His director of communications Ben LaBolt said in a memo to White House staff that the administration should "put a stake in the ground for the future" -- and, in a clear swipe at Trump, spoke of how Biden had restored "decency and dignity to the White House."
With an eye on the history books, Biden is seeking to put his stamp on policy across the board.
On international alliances -- where Trump threatened to drop Western allies if they did not spend more money on defense and held summits with Russia's Vladimir Putin and North Korea's Kim Jong-un -- Biden hosted the leaders of Japan, India and Australia for a farewell summit in his hometown on Saturday.
On climate -- where Trump pulled the United States out of the Paris accords -- Biden wanted to build an "irreversible momentum behind climate action," his National Climate Advisor Ali Zaidi said Monday.
And on Ukraine -- where Trump praised Putin and has been distinctly cool in supporting Kyiv -- Biden is hosting a farewell meeting with President Volodymyr Zelensky at the White House on Thursday to discuss more US support.
"The fact that we do have Gaza, the fact that we do have Ukraine and Sudan issues in our world, just underscores the need for that kind of cooperation," a senior US official told reporters, speaking on condition of anonymity.
Yet the greatest prize of all -- the Gaza ceasefire that Biden set his sights on before he leaves office in January 2025 -- seems further away than ever.
Instead, the situation in the Middle East is becoming ever more dangerous, with the UN General Assembly likely to be dominated by recent Israeli attacks on Hezbollah strongholds in Lebanon which have killed at least 500 people.
Biden "will address the Middle East, especially this very difficult year that we have all gone through" in his speech, the senior US official said.
By Aurelia End With Danny Kemp In Washington