As Putin travels to Italy one of the most important persons he will meet is the Pope.

The meeting of the world’s most powerful Christian leader and the leader of what is fast becoming the world’s most powerful Christian country ought logically to be a meeting of friends.

Putin and Francis do indeed agree on many things.

They have similar - though not identical - views on social issues.  

Both mistrust the free-wheeling capitalism of the West.  

Both have practically identical views on the various conflicts in Latin America and the Middle East.

Notwithstanding this, the meeting is likely to be uneasy.

Though Russia and the Vatican are no longer enemies in the way they were during the Cold War, when the Pope sometimes represented himself as “anti-Communist in chief” and the Soviets sometimes represented the Pope as the apostle of fascism, the differences between them are still profound.

Ever since the election of John Paul II the Vatican has pursued a policy of reconciliation with the Orthodox Church, the largest Christian community outside the Catholic Church.  For this to succeed it requires a rapprochement with what is by far the biggest Orthodox community, which is the one in Russia.

The Vatican has accordingly consistently sought reconciliation with the Orthodox Church in Russia and has pushed for decades for a summit meeting between the Pope and the Patriarch of the Russian Orthodox Church.

That summit meeting has never happened.  

In part that is because of the deep mistrust the Orthodox have of Rome.  

Whereas the Protestant communities of Western Europe have their ultimate origin within the Catholic Church, even if in rebellion against it, the Orthodox Church sees itself as the true original Church and sees the Catholic Church as a heresy.   Some Orthodox go further, even questioning whether it is properly speaking Christian at all.

Beyond these theological questions, there is the constant Orthodox concern, extending back millennia, about the eastward expansion of Catholicism into the Orthodox world.  

This has been a fundamental issue in the conflicts between, for example, Russia and Poland, and it is also a key to understanding the Crimean War.  

Since Rome can never compromise on the question of the Pope’s supremacy, which is unacceptable to the Orthodox, any advance by Catholicism into the east, and any overtures from the Vatican to the Orthodox Church, are bound to be met with skepticism from some and outright hostility from others.

Transcending these questions is however the present conflict in Ukraine.

It is not a misrepresentation to describe this conflict as in some ways a religious conflict pitting the Orthodox of Ukraine’s east against the Catholics of Ukraine’s west. 

The Uniate church that predominates in Ukraine’s western regions, which owes allegiance to the Pope, has been outspoken in its support for the Maidan movement, which it played a key part setting up.  It is also traditionally hostile to Russia, which at various times has sought to suppress it.  

Whilst the Vatican has tried to maintain a distance from the conflict, deploring the war between Christians, it has been inundated with angry calls from the Uniate hierarchy of Ukraine demanding more support.  With the Pope unwilling to offend some of his most devoted followers, this places a constraint on what Vatican diplomacy can do.

The result is that it is difficult to see any further moves towards a Catholic-Orthodox dialogue whilst the conflict in Ukraine remains underway.