WASHINGTON >> The extensive hack of U.S. government computer systems, almost certainly orchestrated by the Kremlin, underscores the daunting foreign policy challenge that President Vladimir Putin of Russia poses to the incoming Biden administration.

Until Tuesday, the Russian leader had yet to acknowledge the Biden victory, and for weeks Kremlin-backed news outlets had gleefully amplified President Donald Trump’s groundless claims of election fraud.

“I am ready for contacts and interactions with you,” Putin said in a message of congratulations to President-elect Joe Biden, according to a Kremlin statement issued Tuesday.

Yet there is little doubt Putin is unhappy that Trump’s see-no-evil approach to Russia is coming to an end, suggesting a tense if not hostile relationship with Biden.

Many of Biden’s key goals — reviving arms control, combating climate change, ending the coronavirus pandemic and stabilizing the Middle East — will require collaboration with a Russian leader who is nakedly hostile to Western interests.

Biden and his national security team must find a way to do that even as they work to check a Kremlin whose troops harass U.S. forces in conflict zones overseas and whose state-sponsored hackers have interfered in presidential elections in the United States.

Although Putin emerged as a clear rival during the Obama era, when Biden was vice president, the incoming president will face an even bolder Russian leader who advances his nation’s interests — and challenges American ones — not only in what Moscow calls its near-abroad but also in Western Europe, Africa, Latin America and the Arctic.

Putin has also become a threat in the United States, emerging as a malignant player in domestic politics whose proxies flood social media with disinformation and seek to interfere in elections, with a clear bias against Democrats like Biden.

“Russia has moved from a classical, conventional nuclear power to an insidious hybrid threat,” said Fiona Hill, who spent more than two years as Trump’s top National Security Council aide for Russia affairs.

“Obama was very dismissive toward the Russians, calling them a regional power; they didn’t want to think about Russia too much,” she said. “But the world has changed completely. Biden can’t do Obama 2.0. They are going to have to think differently.”

Putin’s message to Biden betrayed no hostility and, in the words of the Kremlin, “expressed confidence that Russia and the United States, which bear special responsibility for global security and stability, can, despite their differences, effectively contribute to solving many problems and meeting challenges that the world is facing today.”

Biden has a limited but contentious personal history with Putin, whom he has met only once, during a trip to Moscow in 2011, when Putin was prime minister. After a long and “argumentative” official meeting, as Biden recalls it in a memoir, he joined Putin in his office for a private conversation.

“Mr. Prime Minister, I’m looking into your eyes,” Biden remembers telling him with a smile, a nod to former President George W. Bush’s infamous claim to have done the same and seen his “soul.”

“I don’t think you have a soul,” Biden says he told Putin. The Russian leader sounded something less than offended, replying, also with a smile, “We understand each other.”

Michael A. McFaul, a former U.S. ambassador to Moscow, recalled that trip and said Biden and Putin had a “sharp exchange of differences” about Russia’s approach to the surrounding region, particularly the former Soviet republics of Georgia and Ukraine.

“We went from that meeting at the prime minister’s office to his next meeting with the Russian opposition,” McFaul said. “He had no qualms about that at all. He made news there when he said, ‘I told Putin he shouldn’t run for a third term.’”

Many of Biden’s senior advisers remain bitter about the Kremlin’s interference in the 2016 election, which they blame for helping sabotage a transfer of power from the Obama administration to a Hillary Clinton presidency, and sending many senior Biden officials into a four-year political exile. Putin has also taken on a more sinister cast, more recently with the attempted killing of Alexei Navalny, Russia’s top opposition leader, with a nerve agent, prompting Biden to vow to “hold the Putin regime accountable for its crimes.”

After three Russian warships steamed through U.S. fishing territory off Alaska over the summer, scaring away commercial fishing boats and risking a confrontation, the Trump administration did nothing in response. It was just one of several altercations and close calls this year involving the Russian military that created a state of pitched tension with Moscow, the sort that Biden may be far less eager to ignore.

Putin appears no happier about Biden’s victory over Trump, who displayed admiration and deference toward the Russian leader in ways that baffled and outraged Washington’s foreign policy establishment.

Still, Russia experts, some of whom served with Biden, note that there is no escaping a dual track with Russia, in which the United States tries to keep the Kremlin’s ambitions in check while also working with it on international concerns.

Biden administration officials are likely to have almost immediate contact with the Kremlin in an effort to extend the New START treaty, the Obama-era accord that limits the Russian and U.S. strategic nuclear arsenals to 1,550 warheads and bombs each. The pact expires on Feb. 5 but contains a provision for a five-year extension if both sides agree; a shorter extension is also possible.

That process would not require high-level contacts and could take place through the passing of diplomatic notes and meetings between envoys. Biden and Putin have both said they would like to extend the treaty, which Trump administration officials refused to renew unless it was expanded to include restraints on China’s nuclear arsenal. Beijing, in turn, has said that is an unacceptable demand on its much smaller force.

“I don’t think the Biden administration wants to embark on a costly arms race when it has so many other priorities,” said Angela E. Stent, the director of the Center for Eurasian, Russian and East European Studies at Georgetown University. “Once that is done, I would anticipate they will engage in new arms negotiations. That whole cluster has been ignored for years. That could lead to more stable communication with the Russian government.”

While the Obama administration engaged with Russia on a range of other issues, such as short-lived cease-fires in Syria and a negotiated settlement in Ukraine, others have emerged or gained new urgency over the past four years, including the climate crisis and the coronavirus pandemic, putting new pressure on Moscow to cooperate.

“I think over time, Russia is going to have to change the way they do things not because of our pressure but the sheer weight of the shifts in climate change,” Hill said, noting that thaws in the polar ice cap have led to competition for Arctic shipping lanes near Alaska that never existed before. “There has got to be fresh thinking on these issues.”

Biden is likely to find himself under early pressure from both Democrats and Republicans to crack down on Putin after four years of Trump’s conciliatory gestures.

“Putin’s three objectives are to maintain his power, to restore his sphere of influence around Russia and to return to being a great power of global stature,” said Sen. Jack Reed of Rhode Island, the top Democrat on the Armed Services Committee. “The Trump administration has been more accommodating than anything else.” And Biden, he said, would need to work with international allies to rein in Putin.

Perhaps the greatest legacy of the Trump era when it comes to Russia is the role the Kremlin played in domestic politics. Its documented interventions in the 2016 election left the perception among many Americans — to Trump’s continuing rage — that Moscow helped him win the election. Trump’s refusal to release military aid to Ukraine, which was battling Russian proxies, led to his impeachment.

Just this month, Attorney General William Barr designated the U.S. attorney investigating the origins of the Trump-Russia inquiry as a special counsel, all but ensuring that the Russia inquiry will bleed into the Biden presidency.

The challenge for Biden will be to let it all go, said Hill, who found herself at the center of the maelstrom when she testified before the House Intelligence Committee’s impeachment hearings that Trump had ordered a “domestic political errand” that ran contrary to his administration’s foreign policy.

“How do you resist the temptation some will have for revenge?” asked Hill, who is now a senior fellow for the Center on the United States and Europe at the Brookings Institution. “I am not sure there will be a push for that, but there will be this horrible hangover. There is a real risk of going back to the past vengeance for what happened in 2016.”

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