ROME — On Wednesday, the Vatican’s idea of Europe suffered a mortal blow.

The British government delivered a letter to European Union headquarters invoking Article 50 of the Lisbon Treaty, meaning the two-year countdown to Brexit now begins.

The day before, in Barcelona, British Cardinal Vincent Nichols was somewhat ironically attending a youth symposium sponsored by the Council of the Bishops’ Conferences of Europe, or CCEE.

Nichols wanted to emphasize that a setback for the EU was not necessarily a setback for the continent.

“I speak about Europe, which is not the same as the European Union,” the cardinal said. “This is important to me as a person from England!”

The setting was important. The CCEE comprising the Catholic bishops conferences from throughout the European landmass  is not to be confused with COMECE, which is the Commission of the Bishops’ Conferences of the European Community, and limited only to those nations within the European Union.

This was a difference, given the circumstances, that Nichols felt he needed to highlight.

It is telling that he was the only one making the distinction.

The President of the CCEE, Italian Cardinal Angelo Bagnasco, spoke of “Europe and the European Union.”

Bagnasco, who also serves as president of the Italian bishops’ conference, was affirming the vital importance of the EU in the mind of the Church during the Union’s darkest hour.

Just days ago, on March 24, Pope Francis told EU leaders marking the 60th anniversary of the Treaty of Rome – which established the European Community, the forerunner of the EU – that the founding of the European Union is “linked to today’s hopes and the expectations of the people of Europe, who call for discernment in the present, so that the journey that has begun can continue with renewed enthusiasm and confidence.”

However, as Brexit has shown, “discernment” is causing more and more Europeans to question whether or not the journey of European integration is worth it.

The EU is suffering a crisis: The economy is sluggish, family life is under assault, and the migrant crisis is straining the political will of the member states.

In France, Marine Le Pen’s right-wing National Front party is doing well in the polls, and Italy’s radical 5-Star Movement is considering teaming up with Italy’s separatist eurosceptic Northern League if that’s what it will take to form a government after the next election.

The European Union has survived Eurosceptic governments on its fringes, thinking an addiction to EU transfer funds will, in the end, keep them in line.

But if the core nations of the EU the same ones which signed the Treaty of Rome 60 years ago elect Eurosceptic governments, the very existence of the EU is in jeopardy.

In fact, it is a possibility, remote to be sure, that if the negotiations of Brexit continue as long as some think possible, there might not be a European Union left to leave.

And that is a frightening possibility for the Vatican, which has supported the post-World War II European project from the beginning.

In the eyes of the Vatican, the nationalism which rose up in the nineteenth century – and the breakup of the transnational continental empires after World War I – was a dangerous thing, not only because it was often linked to anti-clericalist and other revolutionary ideas spread with Napoleon’s armies century, but because the Vatican believed Europe should be more, not less, unified.

Pope Benedict XV in 1917 said Christian Europe was destined by history to move toward “a unity that favored its prosperity and glory” as world powers began meeting to try and end the Great War, while at the same time the pontiff suggested an international association to draw nations closer together.

After Europe’s second fratricidal conflict of the 20th century, the Vatican greeted the Treaty of Rome with enthusiasm. Pope Pius XII said for the new European Community to be successful, it would have to have a “political authority which will have sufficient responsibility to be felt.”

He was probably encouraged that the three main drivers of the European project – Frenchman Robert Schuman, German Konrad Adenauer, and Italian Alcide De Gasperi – were not only Catholic, but also from areas of Europe –  Alsace-Lorraine, the Rhineland, and Tyrol, respectively –  which had long been contested by the great European powers, so they would know what was at stake as Europe tried to forge a lasting peace.

This attitude did not change after the third great upheaval on the continent in the 20th century: The end of the Cold War.

Although Pope John Paul II was suspicious of the over-centralization and secularizing tendency in Brussels, he still saw the expansion of the European Union as part of “the process of Europeanization of the whole continental area.”

Of course, there were exceptions – Europe’s microstates didn’t join the EU, and Norway and Switzerland kept out for their own reasons – but as a whole, from post-Franco Spain to post-Yugoslavia Croatia, joining the EU has meant joining the “idea of Europe.”

Of course, this idea is not universally shared. Russia offers its own illiberal model to follow, and it is attractive even to some current members of the EU. Political movements on the far-right and the far-left have used Brussels as a bogeyman to blame for every conceivable national ill.

But for countries such as Serbia and Ukraine, EU membership would still mean “coming of age” on the continent, and having a place at the table.

And for the Vatican, this is important, because that table is a place where conflicts can be resolved, agreements made, and even friendships forged by former foes; where national interests sometimes have to give way to the common good for the continent, where leaders can, as Pope Francis puts it, “in a spirit of solidarity and subsidiarity, devise policies that can make the Union as a whole develop harmoniously.”

All because Europe has meant the European Union.

But if Britain, which more than any other country shows how diverse Europe can be in its culture and institutions, says it’s not worth it and leaves the table, how long before other nations say “Europe is not the same as the European Union”?

And if they all get up and leave the table, what then will Europe be?