A mural depicting GOP nominee Donald Trump and Russian President Vladimir Putin in Vilnius, Lithuania. Trump’s controversial Russia stance has given Moscow an unprecedented role in the election. AFP PHOTO/Petras Malukas/Getty Images

A year ago, not even the most dedicated hackers in Russia’s troll army could have predicted their country would play this big a role in the U.S. election.

But then Donald Trump came along – and Russia suddenly began playing center stage in the campaign.

Much of the Russia talk has come from the GOP presidential nominee’s own boasts about his relationship with President Vladimir Putin — though sometimes Trump tries to walk those back, claiming to barely know him. But it hasn’t stopped there: Trump casually urged Russian hackers to strike against his Democratic rival, hired top campaign staffers with apparent political and financial ties to Russia and its allies, and told CNBC this month that Trump “will be friendly” with Putin if elected.

Trump is arguably the first major party candidate since World War II to speak about Russia so warmly – a tone all the more striking because he criticizes just about everybody else. And his affinity for Russia is helping drive a deep schism in the GOP foreign policy establishment, as lifelong Republicans flock to Hillary Clinton.

But experts say the debate may complicate the critical relationship between Moscow and Washington following the election — even if Trump isn’t in the Oval Office.

“When a foreign policy issue becomes a political issue, it becomes all that much harder to do foreign policy,” said Sam Charap, a Russia expert with the International Institute for Strategic Studies. “It becomes harder to convince in particular senior people, after the fact, to have some sort of relationship with this country.”

After years of sparring over Ukraine and the future of war-torn Syria, Russia was destined to play some role in the 2016 election. But it wasn’t supposed to be like this.

Save for Trump, the this year’s GOP presidential candidates spewed nothing but venom toward Russia: Florida Sen. Marco Rubio called Putin a “gangster” and a “thug;” Ohio Gov. John Kasich said it was “time that we punched the Russians in the nose,” and New Jersey Gov. Chris Christie — now backing Trump — pledged to shoot Russian planes down over no-fly territory in Syria.

Their words were not accidental, but the pinnacle of a case the GOP has been making against Russia — and by extension, the Obama administration — since 2008, when GOP nominee John McCain accused then-candidate Obama of “naivete” for not coming down harder against Putin in that summer’s Georgia war.

This year, the GOP intended to attack Clinton as the chief architect of a failed Russia policy, particularly because it was she who tried to hit the “reset” button on U.S.-Russia relations in her first months as the country’s top diplomat.

“Hillary was going to have to explain the allegedly naïve, unsuccessful reset. We forgot about that a long time ago,” said Stephen Sestanovich, a former U.S. ambassador-at-large to the former Soviet Union and Russia expert with the Council on Foreign Relations. “She’s not on the defensive at all about Russia, and it’s entirely because of Trump.”

Clinton has often talked tough about Russia, particularly since leaving office, charging in 2014 that Putin aims to “re-Sovietize” its neighbors and even likening his rationale for invading Ukraine to Hitler’s moves in the run-up to World War II. But Republicans say that belies her own responsibility as the chief enabler of Russia’s resurgent aggression with the 2009 “reset” that, by most measures, had failed by the time Russia annexed Crimea five years later.

While the Cold War is over, America’s battle of wills with Russia is not. The rivalry continues to play out in Syria, where Moscow and Washington back different factions and disagree over Syrian President Bashar al-Assad’s future. In Ukraine, the U.S. is sanctioning Russia over its annexation of Crimea and continued inference in the eastern regions.  Tense relations complicate Moscow’s and Washington’s dealings with Iran and China. That doesn’t even count allegations that Russia hacked into the Democratic National Committee and other political servers to obtain sensitive material.

Against that backdrop, Trump’s Russia chumminess poses a conundrum for many of the Republicans still backing him.

On Monday, Trump gave a speech  in which he urged closer cooperation with Russia against the Islamic State and never mentioned Ukraine, despite offering confusing recent takes on whether he would recognize the disputed Crimea as part of Russia.

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Afterwards, Senate Foreign Relations Committee Chairman Bob Corker (R-Tenn.) – who praised earlier Trump foreign policy speeches as Reagan-like – was noticeably silent on Trump’s words. Instead, he released a statement detailing a conversation with the U.S. ambassador to Ukraine, noting the worsening situation there and concluding: “we must continue to provide the support we have committed.”

For analysts of U.S.-Russian relations, the dynamics are politically inexplicable.

“The weird thing about Trump’s use of this [Russia] issue is that everything else he does seems to be a kind of crude exploitation of some perceived prejudice of the American people or some part of the electorate,” Sestanovich said. “The whole Russia issue seems totally unrelated: All the polls show that Russia is totally unpopular to the American people…the truth is, most of the ways in which the Russia issue figures in the campaign are kind of unprecedented.”

Trump’s comments have even sparked questions about whether the GOP nominee may be coordinating efforts with Moscow — charges a mainstream presidential candidate hasn’t had to take seriously since 1948, when Henry Wallace, the Progressive Party candidate who was Franklin D. Roosevelt’s vice president, was accused of coordinating with Josef Stalin. In following decades, the icy standoff between the U.S. and the Soviet Union guaranteed that when presidential candidates bickered over Moscow, it was to establish who could talk tougher against America’s greatest enemy.

But the Trump camp has sharply departed from that legacy. Trump campaign manager Paul Manafort is widely credited with orchestrating Putin crony Viktor Yanukovych’s return to power in Ukraine, and was recently accused of receiving $12.7 million in cash payments from Yanukovych’s pro-Russian party — a charge he dismissed as “unfounded, silly and nonsensical.” Meanwhile Trump adviser Carter Page has raised some eyebrows for praising Putin in June as stronger and more reliable than President Obama and calling American foreign policy “hypocritical” during a July speech in Moscow.

“There’s a much higher degree of connectivity now, thanks to 25 years of Russia being integrated with the Western world,” said Matthew Rojansky, director of the Kennan Institute at the Wilson Center. “Paul Manaforts and Carter Pages and DNC servers are in some ways just the unavoidable consequence of living in a globalized 21st century.”

At this point, many Republicans would like to simply sideline Putin. With the backlash against Trump, that pressure is becoming so forceful it may be difficult for any future president to fashion a working partnership with Moscow.

“Nobody was expecting a reset, and things are so bad now it’s hard to see how they get worse…but can we do business with a country that’s perceived as interfering in our elections?” Charap said. “Russia is basically political toxic waste – anyone who touches it, their hand turns radioactive.”

But pragmatically, it has never been possible for the U.S. to fully circumvent Russia.

“In the same week in which everybody is going nuts that Manafort apparently has a sleazy relationship with a bunch of Putin cronies, the White House and the Kremlin are working out details for cooperation in Syria,” said Sestanovich. “The real issues that challenge the Russian-American relationship are going to be policy ones, not personal ones.”

Yet experts say there is a clear incentive for Putin, who has long accused the United States of meddling in internal Russian affairs, to continue to seek to play an outsize role in U.S. elections.

“Russia’s a huge country and Russians aren’t wrong to think that they can shake things up a little bit,” Rojansky said. “If you read the modestly pro-Kremlin analyst types [in Russia], this is consistent with what they’ve been saying all along – that American democracy is not immune from this sort of dirt.”

“The U.S. and Russia are engaged in tit-for-tat,” Rojansky continued. “It’s only to the Americans that lines have been crossed.”