LONDON — A decade ago, Joseph R. Biden Jr. strode into a reception room in Athens for a meeting with the president of Greece, a country then drowning in debt and locked in tense negotiations with the European Union.
“This man represents the Treasury Department,” a deadpan Mr. Biden said to his host as he gestured to a gray-suited member of his delegation. “He’s brought hundreds of millions of dollars.”
The room broke up in laughter: It was clear the vice president hadn’t come with a briefcase of cash to pay off Greece’s debts. But his joke captured a deeper truth — in 2011, many still viewed the United States as the ultimate guarantor of the international order. And Mr. Biden clearly saw himself as a steward of that legacy, his easy self-confidence the product of four decades as a globe-trotting senator.
As Mr. Biden took the oath of office on Wednesday, vowing to “repair our alliances and engage with the world once more,” the question for many overseas is whether they will see this man of the world anytime soon.
In capitals from Europe to Asia, diplomats and foreign-policy experts have questioned whether the United States is too divided, too weakened and too preoccupied by internal convulsions to play the kind of leadership role that Mr. Biden took for granted as a senator and vice president.
Yet there are reasons to believe President Biden will be more visible and activist than many expect, even as he grapples with the pandemic, a massive economic recovery effort, and the deep divisions left by the Trump era. From the people he has chosen for key foreign policy posts to the travel opportunities he has this year, those who know Mr. Biden say he is unlikely to stay off the global stage for long.
“This is a guy who spent 40 years getting to know foreign leaders around the world,” said Peter Westmacott, who lived next door to Mr. Biden as British ambassador to Washington during the Obama administration. “Once you’ve got a flavor for international relationships, you don’t turn your back on all that.”
Wolfgang Ischinger, a former German ambassador to the United States, said he expected Mr. Biden to draw on his personal relationships to mend bonds with European allies that had been sundered by former President Donald J. Trump.
“Joe Biden is a master of networking, and he will easily repair the lack of trust,” said Mr. Ischinger, who now runs the Munich Security Forum.
Mr. Ischinger’s immediate goal is to persuade the president to attend his influential annual conference. He has a decent chance of landing him: Mr. Biden has been a staple in Munich for years, most memorably in 2009, when he announced that President Barack Obama wanted to hit the “reset button” with Russia.
In his inaugural address, Mr. Biden said the “world is watching.” He promised that the United States had “come out stronger” from its recent stress test. And he pledged a restoration of American leadership in which, he said, “we’ll lead, not merely by the example of our power, but by the power of our example.”
Mr. Biden is likely to make his formal debut at a meeting of Group of 7 leaders in June, which Britain is hosting at a seaside resort in Cornwall. He may expand that trip to include other European destinations, including Germany, where he could bid farewell to Chancellor Angela Merkel before she steps down after 16 years.
In the fall, Mr. Biden is expected to attend a Group of 20 meeting in Rome and the United Nations’ climate change conference in Glasgow, Scotland, where he could showcase his decision to rejoin the Paris climate accord.
Beyond dates in the diplomatic diary, experts contend that Mr. Biden’s appointments do not suggest an inward-looking White House.
His choice of Kurt M. Campbell to serve as a high-level coordinator of Asia policy, for example, could foretell a tough line with China coupled with an energetic effort to reassure American allies Japan and South Korea. As a State Department official in the Obama administration, Mr. Campbell devised the so-called “pivot” to Asia.
“Biden has chosen people who understand and are committed to strategic competition,” said Thomas Wright, a foreign-policy expert at the Brookings Institution.
Some experts argue that the chaos at the Capitol had compromised the nation’s traditional role as a champion of democracy, and that the cascading domestic crises would consume Mr. Biden’s energy, distracting from world affairs.
“Ambitious foreign-policy goals are completely out of step with the realities of the country’s domestic political and economic dysfunction,” Emma Ashford, a senior fellow at the Atlantic Council, wrote in Foreign Policy. “How can the United States spread democracy or act as an example for others if it barely has a functioning democracy at home?”
But Mr. Wright argued that the homegrown threats to democracy should strengthen the Biden administration’s resolve to fight human-rights abuses by China, Russia, and other autocratic governments.
“I’ve never understood the trade-off between ambition at home and ambition overseas,” he said. “It’s precisely because democracy is challenged at home that the U.S. needs to be more energetic in defending democracy overseas.”
The links between domestic and foreign policy were reinforced by the appointment of Susan E. Rice, who served as national security adviser to Mr. Obama, as director of Mr. Biden’s domestic policy council. Key domestic priorities like the pandemic, experts pointed out, are also global challenges.
Another top Biden aide, Jake Sullivan, the national security adviser, used Twitter to weigh in on sensitive issues before his boss took office. He condemned Russia’s arrest of the opposition leader Alexei A. Navalny, appealed to the European Union to think twice before signing an investment treaty with China, and said Mr. Trump’s designation of the Houthi rebels in Yemen as a terrorist group “will only inflict more suffering on Yemeni people.”
Whether the Biden administration will back up those words with action remains to be seen, of course. But some say that Mr. Biden’s instincts, temperament and background as a longtime member of the Senate Foreign Relations Committee make him unlikely to shrug off chances to command the world stage.
As vice president, he reveled in his access to world leaders. On a trip to Turkey in 2011, there were doubts that President Recep Tayyip Erdogan, who was recuperating from a medical procedure, would see him. Instead, Mr. Erdogan invited him to his private residence, where the two men, wearing slippers, spoke for two hours about Syria and Iran.
“I don’t want to sound like I’m inflating my importance or relationship with him,” a chuffed Mr. Biden told reporters, “but we have listened to each other. And he was genuinely listening to my perspective and wasn’t challenging it.”
At other times, Mr. Biden has taken pride in his readiness to speak bluntly to foreign leaders. He famously walked out of a dinner with Afghanistan’s president, Hamid Karzai, in 2009 after a rancorous exchange over corruption.
In 2012, Mr. Biden was assigned to play host to Xi Jinping, then China’s vice president and designated future leader, when he visited the United States. Toasting Mr. Xi at a Valentine’s Day lunch, Mr. Biden ran through a litany of grievances, from Chinese theft of intellectual property to human rights abuses.
“Cooperation, as you and I have spoken about, can only be mutually beneficial if the game is fair,” Mr. Biden said as Mr. Xi looked on.
On a trip to China the following year, Mr. Biden publicly criticized China for refusing to say if it would renew the visas of American correspondents and for blocking the websites of American-based news media. Several years later, China expelled correspondents for The New York Times and other publications.
Speaking as a president, to be sure, is different than as vice president. During his trip to Greece in 2011, Mr. Biden ruminated about the risks of commenting on the fiscal tensions between Greece and the European Union.
“You know, in the good old days when I was a senator, I was my own man,” Mr. Biden told reporters at the time. “I could just tell you my views. But now whatever I say is attributed to the administration.”
“I finally learned that,” said the man who now leads his own administration. “It took me about six months, but I got it down.”