US President Joe Biden will soon name his ambassadors to serve in the capitals of some of the most crucial countries around the world. Australia will likely be in the mix, following reports that Caroline Kennedy may be headed Down Under.

The calibre of the people Biden choose will be consistent with the deep experience and record of service he has captured for his cabinet and his senior staff. Equally important, these ambassadors, by dint of their relationship with the President, will be able as needed to reach directly into the Oval Office, to ensure there is no lapse in strategy, execution or communication on the foreign policy responsibilities they carry.

Here's a memo to the Biden class of ambassadors.

The most important job you have in these first years of Biden's presidency is to restore and repair the credibility and standing of the United States as a world-leading democracy. The very sad fact is that - as a result of President Trump's trashing of America's values, his disruption of critical alliances forged after World War II, and his hostility to the global architecture that has preserved and defended security, peace and prosperity for decades - America not only retreated from world leadership, but left most of the world distressed and despondent about American democracy and its resilience as a touchstone for the world.

Biden's ambassadors therefore have a task not only of taking care of the US foreign policy business at hand, but in recrafting perceptions about the United States and its democracy. There is no doubt Biden is even more popular in many countries overseas (likely including Australia) than his already very positive ratings at home (about 60 per cent approval).

But can Biden - and America - be trusted?

While overall views of the US have improved since Biden's inauguration on January 20, global political sentiment remains very troubling. Even in Australia, US favourability is below 50 per cent. The Alliance of Democracies recently assayed 50,000 people in 53 countries. 44 per cent believe the United States threatens democracy in their countries. That is not the worst of it. Fear of China as a threat to democracy was only 38 per cent, and Russia just 28 per cent.

What would drive such sentiment? Put baldly: repellent perceptions of how American democracy is faring these days. The former president has rejected the result of the 2020 election, claims his successor is an illegitimate president, and was impeached for provoking a violent insurrection against the Congress. Seventy per cent of Americans who identify as Republicans believe the election was stolen, even though every state, 60 court rulings and Trump's own attorney-general attested to the election's veracity. Two-thirds of the Republicans in the House of Representatives voted to overturn the election result. Trump and the Republican party are now purging those who have had the courage to speak up against their big lies. Dozens of states controlled by Republicans are passing restrictive new laws to suppress voter turnout - to impede their citizens, and especially people of colour, from exercising the essence of a democracy: the right to vote. Black Americans are at high risk of being killed by police. Gun violence is out of control, and Congress refuses to take even primitive measures to limit it.

All of this is captured on social media every day. Informed peoples around the world see it, absorb it, and process it.

China now dismisses American democracy with abandon, and relishes the chance to present its system as superior to that of the United States.

Can Biden navigate this maelstrom? And if he cannot - if the next president is, if not Trump, a retread of Trumpism - will his successor reverse all the efforts Biden has undertaken to rebuild alliances with Western democracies and America's strategic allies, repudiate again international agreements made, and renew the corruption of America's democratic institutions?

To invoke the words of Ronald Reagan, world leaders may trust Biden, but can they verify that America's commitments to the values and priorities and policies he represents are in fact enduring?

Not yet.

The task, therefore, for the Biden class of ambassadors is to be unflinchingly honest about the course under President Biden's leadership: that America is back and on the move again, that the President is rebuilding, restoring and renewing America's capabilities, and is facing up to those doubts about America's democracy

National Security Adviser Jake Sullivan expanded on this theme in his press briefing just before President Biden's trip to Europe.

"We are in a competition of models with autocracies, and we are trying to show the world that American democracy and democracy writ large can work, can effectively deliver the will of the people. And to the extent that we are not updating, refurbishing, revamping our own democratic processes and procedures to meet the needs of the modern moment, then we are not going to be as successful in making that case to the rest of the world - to China, to Russia, or to anyone else."

This is why it is still never wise to bet against the United States.

For the new Biden ambassadors, who will be the face and voice of the United States in their posts, this is the only viable road to turning around the sentiment behind the alarming views of billions of people about the United States, its leadership and its staying power. These new diplomats know it. Hell, that's why they will accept the job.