Biden had meetings scheduled with leaders of conflict-torn states such as Iraq, Afghanistan and Ukraine and with major world figures such as Japanese Prime Minister Shinzo Abe.
President Barack Obama even turned over his chair to Biden to run a session on combating ISIS after opening it in the morning. The switch was too much for one of the participants, Danish Foreign Minister Kristian Jensen, who slipped and referred to Biden as "Mr. President ... Vice President, sorry," before quickly adding, "Well, could have been! Can be! Who knows? If you have ... news to tell us here, please let us know."
Although his U.N. trip might look like an effort to stress his leadership qualifications, it's certainly not unusual for Biden to immerse himself in foreign policy. He was on the Senate Foreign Relations committee for decades. He circumnavigated the globe multiple times as vice president, and Obama has given him some of the administration's trickiest national security portfolios.
But these are no ordinary times for Biden. As Democratic front-runner Hillary Clinton
struggles to halt a slide in the polls -- in a campaign in which she, too, is positioning herself as a foreign policy expert given her role as secretary of state in the first Obama administration -- the vice president's stock is rising.
There is intense interest in Biden's intentions as he searches his soul over whether to launch a presidential campaign and emerges from an agonizing period of mourning for his beloved son Beau, who died of brain cancer in May.
Biden might not have made up his mind. But he's hardly been hiding his belief that he has the chops to serve as commander in chief.
Biden: 'I know these guys'
"I've traveled, as of today, 992,894 miles for the President. I've met with virtually every major leader in the world. I know these guys. I know them better than anybody in the administration, because I've been hanging around so long," the vice president told Jewish community leaders in Florida earlier this month, in a remark that might have been a dig at Clinton, who left the State Department after one term.
Then, in a flurry of name-dropping of heads of government from Ukraine to Israel to China, Biden said the questions he got were the same "no matter whether I'm trying to work out something with Poroshenko in Kiev, whether I'm sitting with Bibi in his home in Tel Aviv, whether I'm down with Dilma in Brazil, whether I'm with Xi for five hours in Beijing."
Biden's implicit point was that while other potential candidates might brand themselves national security specialists, he has been a fixture on the global statesman circuit for years and would have no learning curve in the Oval Office.
That is a point he would no doubt make if he were to match up against a GOP rival touting his or her own foreign policy credentials, such as Florida Sen. Marco Rubio or former Hewlett-Packard CEO Carly Fiorina on a presidential debate stage in October 2016.
At the United Nations on Tuesday, Biden was relishing what he told his press pool were "interesting" meetings with foreign leaders that highlighted his global reach and followed on his meetings at the U.N. last September, including with leaders of Pakistan and Iraq.
Biden has been especially involved in Iraq policy, essentially serving as the administration's point person on the issue and talking key players through successive political crises in Baghdad. It's a role that was filled in the previous administration by George W. Bush himself, but Obama has delegated it.
The vice president's meeting with Iraqi Prime Minister Haider al-Abadi on Tuesday came at a sensitive moment, after Iraq reached an intelligence-sharing deal with Russia and Iran over the weekend.
In recent months, Biden's suggestion of dividing Iraq into three states along sectarian lines -- mocked widely at the time when he proposed it during the George W. Bush presidency -- has come to look prescient.
Biden also met Afghanistan's No. 2 Abdullah Abdullah on Tuesday after the Taliban overran the key city of Kunduz, which dealt a blow to the administration's argument that Afghan forces can now ensure security in the war-torn nation without U.S. help.
And talks with Cypriot President Nicos Anastasiades were the latest in the vice president's exhaustive diplomatic effort to broker a political settlement between the Greek and Turkish Cypriot communities on the divided island.
He's been the administration's main point of contact on Ukraine since before Russia's annexation of Crimea last year and deepened his engagement Tuesday in talks with Ukrainian President Petro Poroshenko.
Biden was also given the assignment of making the first senior-level contacts with Xi Jinping before he became China's president in 2013.
That friendship offered Biden a segue into his own political predicament last week when he remembered Xi's pilgrimage to see old friends Iowa in 2012.
"I should have gone," Biden laughed. "He went and became president. I didn't go and I'm still vice president. I don't know what the hell is in the water in Iowa, but it worked."
A double-edged sword
Should Biden chose to swap global statesmanship for the early voting state in the coming weeks, however, he will discover that his foreign policy record is not an unalloyed asset.
Amid chaos in the Middle East and rising challenges to U.S. power elsewhere, the Obama administration record abroad to which Biden is heir is mixed at best.
And the vice president himself has admitted that he would not have ordered the raid to kill Osama bin Laden, perhaps the most successful decision of the Obama administration -- though his candor might win him points among voters craving authenticity.
Biden is also linked to struggling U.S. foreign policy on Russia, Syria and the wider Middle East, and if public sentiment turns hawkish, he could suffer for managing Obama's troop withdrawal from Iraq and opposing a surge in Afghanistan.
Republicans also have plenty of ammunition to use against him, not least a comment by former Obama Defense Secretary Robert Gates in his memoir that Biden was "wrong on nearly every major foreign policy and national security issue over the last four decades."
The GOP is certain to highlight Biden's record of missteps to undercut his record as a statesman and to throw a spotlight on his long reputation for gaffes.
Last year, for instance, Biden referred to Singapore's late patriarch Lee Kuan Yew as "the wisest man in the Orient" -- a term that some Asians find offensive. On a China trip in 2011, Biden was accused of mistakenly endorsing China's one-child policy, which Washington sees as an infringement of human rights.
Still, given the thousands of miles under his belt on Air Force Two, political opponents will have to prove Biden is wrong on foreign policy rather than unprepared -- after all, he was chosen for the Democratic ticket by Obama back in 2008 in part to make up for the latter's own lack of experience on national security.
If he does run, one small vignette on Tuesday could be an omen.
Obama handed over the chair of the ISIS meeting in a U.N. conference room to his vice president with a handshake -- in a moment that Biden might hope could augur a much more important passing of the baton on the west front of the U.S. Capitol in January 2017.