Vladimir Putin and Kirill, the patriarch of the Russian Orthodox Church, participate in a ceremony at a monastery near Moscow in 2017.Sputnik Photo Agency / Reuters

“This is a victory of good over evil, light over darkness.” That’s how Ukrainian President Petro Poroshenko described the announcement Thursday that the Orthodox Church’s Istanbul-based leader, Patriarch Bartholomew, will grant Ukraine’s Church independence from Russia.

In televised remarks, Ukraine’s president dubbed this a “historic event,” which it undoubtedly is: For more than three centuries, Ukraine and Russia have been religiously united within the Russian Orthodox Church. It was a union Poroshenko characterized this summer as a “direct threat to the national security of Ukraine,” given his view that the Russian Orthodox Church fully supports Kremlin policy; he said then that it was “absolutely necessary to cut off all the tentacles with which the aggressor country operates inside the body of our state.”

Now, four years after Russia annexed the Ukrainian peninsula of Crimea, Ukraine is asserting its territorial independence by demanding its own national Church. For Russia, the crisis is geopolitical as well as spiritual. The stakes are so high that in order to protest Ukraine’s religious autonomy, Russia may respond harshly enough to trigger a deep schism in the Christian world.

At the core of this issue is a fundamental question of both religious and territorial identity, as Russian actions in eastern Ukraine aimed to undermine the country’s very independence. The Ukrainian Church had sought independence from the Russian one for decades, but it only became “inevitable after the Russian military excursion in eastern Ukraine, no question about it,” said Aristotle Papanikolaou, a co-chair of Orthodox Christian studies at Fordham University. Ukraine will join several other countries that have their own independent national Churches, among them Serbia, Greece, and Romania.

The Russian Church claims that Ukraine and its backers are the ones pushing the Church to the brink of catastrophe. A top Russian Church official said that by supporting Ukraine’s bid for an independent Church, Istanbul “threatens the global Orthodox world with a schism.” That schism would have an outsized effect on Russia: Severing ties between the Russian Church and its parishes in Ukraine would strip Moscow of a crucial component of its sphere of influence to its west. George Demacopoulos, the other chair of Orthodox Christian studies at Fordham, told me an independent Ukrainian Church would strip the Russian Church of a third of its jurisdiction, and Russia would “symbolically suffer a very big blow because they have been presenting themselves as the leaders of the Orthodox world in the 21st century.”

The Moscow Church “is frequently accused of being a tool of the Kremlin,” Katherine Younger, who directs the Ukraine in European Dialogue program at the Institute for Human Sciences in Vienna, told me. She said she believes that’s why Poroshenko portrayed the issue of Church independence “as a matter of state security”— it’s “a way to weaken a major ideological interference and source of Russian propaganda.” Poroshenko’s apparent concerns have some basis in fact: The Russian hackers indicted by the U.S. special prosecutor in July have tried for years to access private correspondence from top Orthodox Church officials, according to an investigation by the Associated Press. And beginning with the 2014 invasion of Crimea, the Russian Orthodox Church—which is not technically affiliated with Vladimir Putin and the Kremlin—has been accused of spreading “misinformation” about Ukraine.

There are a few different ways Russia could react to Patriarch Bartholomew’s announcement. It could withhold recognition of Ukraine’s Church, which would be a purely symbolic statement of disapproval. Or, according to Demacopoulos, Russia might take “the nuclear option of breaking sacramental unity,” which means people who belong to Orthodox Churches aside from the Russian one could not receive communion while in Russia. That might not sound like much to outsiders, Papanikolaou said, but “it’s a pretty severe step.”

The fight over the Church goes back to a single event that took place more than 1,000 years ago. In 988, Vladimir the Great, the prince of an empire known as Kievan Rus (and Putin’s namesake), converted to Christianity in what is now Ukraine. Russia claims that empire as the birthplace of its historical heritage as a nation. But Ukraine does, too, and Ukraine is the country that actually has Kiev in its territory.

In 2014, Russia annexed the Ukrainian peninsula of Crimea. In a speech at the Kremlin, Putin argued that Crimea belongs in Russia, since ethnic Russians form a majority there. His reasoning also extended beyond Crimea: He seemed to declare that Ukraine and Russia (and Belarus, a smaller player in the ongoing geopolitical tensions) have always been joined together as “one people” through the Church. “Kiev”—the Ukrainian capital city, in the middle of the country, far from Crimea and Russia—“is the mother of Russian cities,” Putin said. All of this, he explained, stemmed from Prince Vladimir’s “spiritual feat of adopting Orthodoxy” more than a millennium ago.

If this battle of religious and national autonomy has been raging for so long, why is it reaching its climax right now? Ukraine first sought Church independence in 1921, after World War I, but the movement has steadily grown since the 1990s, when the Soviet Union fell and Ukraine again became a sovereign nation. Now, Younger explained, “the catalyst is a calculation by Poroshenko,” who can leverage Thursday’s announcement—for which he spent months lobbying—in the lead-up to presidential elections next March. “The creation of a canonical … Church in Ukraine would be a major win for [Poroshenko],” Younger said. “I get the sense that the administration is casting about for a win.”

A spokesperson for the Moscow Church, Vladimir Legoyda, said last month that Russia “will break the Eucharistic communion” with the Church’s central body in Istanbul if Ukraine receives independence. Despite Russia’s stern warnings, Demacopoulos and Papanikolaou, the Fordham professors, don’t think it will take that severe step. Instead, they believe the other independent Churches will slowly line up to recognize Ukraine’s Church, even though it might take Moscow several generations. “You have to understand,” Demacopoulos said, “that this is a 2,000-year-old Church, so that’s not that much time.”

The Orthodox Church might recover, but Russia-Ukraine tensions will likely deteriorate even further. It boils down to whether Russia can continue to be, as Putin portrays it, the standard-bearer of the Orthodox tradition, even with far fewer adherents and far less territory than it previously enjoyed. Framing himself as “the political defender of Christians” has helped Putin rally national support, Demacopoulos told me. It’s no surprise that he isn’t prepared to relinquish that part of his image.

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