After their afternoon summit in the Swiss capital, Biden said give him time to see if his approach works -- trying to play to Putin's long desire to have Moscow seen as a key power, respected and feared around the globe.
For his part, Putin reveled in the role of world statesman again and the platform the summit gave him -- smiling before the cameras, fielding questions from several reporters, and defending his government on human rights, foreign interventions, and cyber space.
In contrast, Biden seemed to go to lengths to boost Russia's importance. During their first photo op, the president called the U.S. and Russia "two great powers" -- an equal standing that Putin has long sought since coming to power in 2000 in the turbulent -- and to many Russians, ignominious -- post-Soviet years. In the days before their meeting, he called Putin a "worthy opponent" and "bright."
Putin seemed to respond to the compliments, too, telling his own post-summit press conference that Biden “perfectly knows the matter” and “what he wants to achieve, and he does it very shrewdly.”
Biden: 'We'll find out within the next six months to a year'
Even holding the summit itself, which many critics called a concession by Biden, and so early in his term -- before meeting China's President Xi Jinping, for example -- could play to the self-importance that Putin desires.
But whether that will change any of the destabilizing behavior that U.S. officials have tried to counter through sanctions and other penalties for years seems unlikely, according to critics and some analysts, who argue that the instability and unpredictability that Biden says he wants to tamp down is so critical to Russia's power.
"It is clear to me that Putin could care less about how he's viewed by others and, quite frankly, would enjoy the reputation of being able to successfully interfere in the internal matters of other countries," according to Sen. Lindsey Graham, R-S.C.
But to other analysts, the summit is about achieving pragmatic steps on issues of deep concern, while laying out in advance for the Russian president clear red lines and threats of retaliation.
"None of this means that the U.S.-Russian confrontation is on the way out or even being eased. However, there is some expectation that from now on it might be better managed or even regulated," said Dmitri Trenin, director of the Carnegie Endowment for International Peace's Moscow Center.
Out of the summit, the two sides agreed to hold further talks on nuclear arms control, cybersecurity, diplomatic relations, and a possible prisoner exchange.
Biden urged patience on all those fronts, telling reporters Wednesday, "This is about practical, straightforward, no-nonsense decisions that we have to make or not make. We'll find out within the next six months to a year."
Biden ally: Wait-and-see approach won't work
Some critics, like the top Republican on the House Foreign Affairs Committee, Michael McCaul, said that giving Putin that stage was a concession alone, especially given that the increasingly authoritarian Russian leader has not changed his behavior for years in the face of U.S. and Western pressure.
Even Biden allies like Ben Rhodes, former President Barack Obama's deputy national security adviser, said that his wait-and-see approach won't work.
"We made a lot of judgments that were actually quite similar to what Biden was describing in the press conference yesterday. … And I don't think that's the right way to think about Putin," he said Thursday. Instead of wanting "certain standing on the world stage," he added, Putin "wants to do things on the world stage that are either disruptive to democracy itself or disruptive to international order in ways that will force people to reckon with him."
But Biden's approach is different in rhetoric from Obama's, which could make a difference in Moscow.
Obama was repeatedly dismissive of the threat from Russia. During a 2012 presidential debate, he jabbed his opponent Mitt Romney for calling Russia the greatest geopolitical threat, saying, "The 1980s are now calling to ask for their foreign policy back because the Cold War has been over for 20 years."
Two years later, after Russia invaded Ukraine's Crimean Peninsula and eastern provinces known as the Donbas, Obama dismissed Russia as "regional power that is threatening some of its immediate neighbors - not out of strength, but out of weakness" in 2014.
In contrast, Biden seemed to go to considerable lengths to boost Russia's importance. During their first photo op, the president called the U.S. and Russia "two great powers" -- an equal standing that Putin has long sought since coming to power in 2000 in the turbulent, and to many Russians, ignominious post-Soviet years. In the days before their meeting, he called Putin a "worthy opponent" and "bright."
Even holding the summit itself, which many critics called a concession, and so early in his term -- before meeting China's Xi Jinping, for example -- could play to the self-importance that Putin desires.
Could small steps lead to larger agreements?
Whether or not that flattery will win him any changes in Russian behavior remains to be seen. But even small ones on the few areas of talks that both sides agreed to could be baby steps towards stabilizing relations and letting Biden focus his foreign policy elsewhere at times.
They could also grow into substantial agreements, especially on nuclear arms control. Both leaders have not only expressed interest in it, but also demonstrated it already by agreeing to extend the last nuclear arms control pact known as New START in early February.
The takes could not be higher, too. With just that one nuclear arms deal between them, the U.S. and Russia possess more than 90 percent of the world's nuclear weapons at a time when the total number of bombs around the world is growing and still capable of destroying the planet many times over.
In a joint statement afterwards, the two leaders agreed, "A nuclear war cannot be won and must never be fought" -- echoing former President Ronald Reagan, Soviet Premier Mikhail Gorbachev, and their 1985 summit in Geneva.
More important, to some analysts, is that after Wednesday, Putin now knows directly from Biden that progress on these issues will have specific consequences. Although he declined to share details with reporters afterwards, Biden said he warned Putin in detail about U.S. red lines, including 16 kinds of targets in critical U.S infrastructure that if hit by Russian or Russian-supported cyber attacks would result in "significant" responses.
"That specificity is far more likely to succeed in deterring Russian bad behavior than a generic warning about violating international norms," Emma Ashford, a senior fellow at the Atlantic Council, told the New York Times Wednesday.
Even simply returning ambassadors to the other's capital could help improve relations, with the tit-for-tat cuts in staffing and consulate closures by both sides making the work of diplomacy more difficult and the opportunities for dialogue less frequent.
"If we're able to start normalizing the situation of the embassies, it would contribute to not only more comfortable conditions for our diplomats, but also it would contribute to a better climate for U.S.-Russian dialogue because angry people on both sides -- it's not quite constructive in terms of addressing serious and complex subjects," said Dimitri Simes, president and CEO of the Center for the National Interest in Washington.
Both sides have now confirmed their envoys -- U.S. Ambassador John Sullivan and Russian Ambassador Anatoly Antonov -- will return by the end of the month.
But one issue that could swiftly unravel Biden’s gamble is the fate of opposition leader Alexei Navalny, who Putin had poisoned and threw in jail upon his return to Russia. The strongman wouldn’t even reference his name Wednesday, dismissing questions from ABC News and others about political opposition.
Biden told reporters after the Geneva meetings that the death of Navalny in Russian government custody would bring “devastating” consequences — one red line for which he’ll be expected to follow through.