Europeans often view the abiding religiosity of their American cousins with an equal mix of incomprehension and disdain. Americans, they believe, are incurably addicted to parading a simplistic Christianity through every public discussion. Europe, they sniff, left the religious wars behind in the seventeenth century.

Witness Europe’s surprise, then, when the normally dull-to-the-core European Union suddenly got tangled up over whether to write God into its new constitution.

For a year the “European Convention” has discussed a major revision of the EU’s founding documents to make the Union more democratic, transparent and efficient. The Convention has decided to replace the hodge-podge of indecipherable treaties with a relatively simple constitution for the growing Union.

Constitutions—as Europe’s aspiring James Madisons can tell you—are tough to write. The nuts and bolts issues are thorny enough: Should Europe have a Senate? One president? Maybe two? But every constitution must also have a preamble stating the fundamental principles upon which the Union is formed. That’s where God comes in.

The current draft makes no mention of God or Europe’s Christian heritage. Instead, the “values” article states: “The Union is founded on the principles of liberty, democracy, the rule of law, respect for human rights and fundamental freedoms and for spiritual and moral values. . . .” The lack of clear reference to religion has disappointed some Protestant groups, but Catholics are most upset. Pope John Paul II has led the charge, making it a personal—dare we say—“crusade” to persuade Europe to insert religion in the preamble. A reference to Europe’s Christian heritage, he argues, would recognize believers’ “identity and specific contributions to the life of European societies.” In addition to the Pope’s efforts, some Catholic lobbyists and politicians have suggested a clause acknowledging that European values include the values of those who believe in “God as the source of truth.”

These Catholic protests have angered and embarrassed many Europeans who think the church has overstepped its boundaries. The British Humanist Association has called it “shameful for the churches to act in a partisan way.” But before European leaders dismiss the church as irrelevant, they should consider the sources of public support for their cherished Union.

First, Catholic-dominated Christian Democratic parties have fostered European integration without wavering since the early post-war period. Christian Democrats founded the original Community in the 1950s and have often been the force behind major steps to integrate. Europe’s Social Democrats, by contrast, backed integration only belatedly and in several countries remain deeply divided over the process.

Second, the Catholic hierarchy, often working alongside the Christian Democrats, has actively supported integration—especially when the chips are down. For example, the Church has been crucial to EU referendum victories in Ireland, most recently in last year’s crucial vote on the Nice Treaty. And if the Poles vote to join the Union this year, it will be due in large part to the support of the bishops, who will have to face down their own right-wing Catholic opposition.

Finally, the EU attracts its strongest backing from ordinary Catholics. Several studies of European public opinion show that Catholics, especially devout churchgoers, support the EU more strongly than any other religious group. Even when factors such as gender, age, class, education, and party identification are taken into account, Catholic devotion remains an extraordinarily powerful predictor of approval for the EU. This relationship has persisted since the first survey evidence became available in the early 1970s.

The religious landscape of Europe has, of course, changed in recent decades. And this should concern European leaders. While Protestants were once more skeptical about the EU than other groups, now the fast-growing “secular” camp has overtaken them in opposition. Secularism even dampens enthusiasm for the Union among groups who benefit economically from integration—and further depresses it among economic losers. In contrast, Catholic devotion tends to boost EU support among both economic winners and losers.

Catholics remain the most ideologically committed Europeans—they are Europe’s true believers. That commitment will be crucial if European unity is to weather the economic and political storms that will inevitably buffet an enlarged Europe. Europe’s leaders would do well to remember the EU’s core supporters when deciding if God gets a line in the constitution.

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